Its not a easy nor a nice job, but someone have to do it. Otherwise people would start suggesting Robo Unicorns with Drill Horns and Laser Eyes That fart Rainbows whenever it moves.
people never get that far they usually post a lightning rod suggestion first and find themselves on the business end of alblaka's shotgun 
Why are empty Energycrystals/Lapotrons not stackable like the RE-Batteries? And why are the Full ones not stackable?
That would solve some problems, and you could take a 16-Stack of empty/full Lapotrons with you.
Just to help your Idea. Originally i came here to say, that we don't need more Batteries, but then i read your post and, yes they could be stackable.
as to why not stack crystals. i don't know! why couldn't we stack bread for the longest time? and as to the need of batteries. i dispute that we need melon batteries! (lol)
theoretically since the machine cant tip over you only need one leg to drag you along
i think that breaks the illusion that it is nuclear powered
why not using uranium fuel and jetpack starts heating *it shows text messages* then after it reaches critical heat it shuts off instantly and needs to be cooled either by standing in water, nearby ice , placing inside reactor + heat dispenser , combining with ice or water buckets in crafting grid.
cause we want this to be considered an upgrade from the electric jetpack and running back to the canning machine is inconvenient enough(i'm actually thinking about dropping the canning machine part to)
EDIT: also to answer an earlier question the uranium cell will always be considered consumed and unrecoverable(thermal shock)
you have to replace the uranium every full cycle but the jetpack will run out of coolant well before that so its real flight time is up to how long the coolant lasts and that's a number that would be up to alblaka to balance.
EDIT: SpwnX radiation is a myth wake up sheeple! don't be fooled by those slick solar panel sales men the truth is in the atom! here try this grab a marshmallow and stand next to your nuclear reactor if it roasts its self you reactor is just hot if it turns green(which it won't) then its radiaition.
Name: Nuclear Jetpack
Description: [WARNING: some of the following maybe purely for flavor] The Nuclear Jetpack is a miniaturized iridium reinforced nuclear reactor core that has been striped of all its energy making bits to save weight and in their place is added airscoops, failsafes, and a pressure chamber. The logical way it works is a uranium cell heats forced in a air and coolant mixture from one of the jetpack and when sufficient pressure is built up directs them out the other end of the jetpack allowing the jetpack to propel buster steve into the air. When the reactors supply of coolant is expended an integrated redstone fail safe is triggered and the reactor core shuts down. the jetpack can be "refueled" by placing it and 4 cooling cells in a canning machine. After a certain period of flight time (however long a full reactor cycle is) the jetpack's uranium will be depleted (prducing a depleted nuclear jetpack) and requiring it to be refueled for real this is a simple process of poping the jetpack and a uranium cell in a crafting grid to replace the jetpack's uranium cell. In all cases the jetpack carries enough pressure reserves to reach sea level and forces is low the operator to land safely when pressure is low. The jetpack also features an unlimited fight cieling(ok 256m the word of jeb has spoken) and hover move.
recipe:
ingredients: 1 reactor core, 4 coolant cells, 1 advanced circuit, 2 iridium plates, 1 uranium cell
then just strap it on and let'r rip!(pun intended "green steam"(flavor not serious))
ill suggest it then. iridium would make sense for for protecting steve from heat and radiation(though its still a myth)
because of the way minecraft physics work its probably best to either avoid water as fuel like the plague or assume all ic2 tech where water makes sense has a built in infinite water supply (the only exception being watermills)
EDIT: actually we can fuel it with cooling cells its explains fuel, safety, and thrust medium all in the same package that fits in a canning machine 
EDIT:EDIT: can an item keep track of 2 fuel sources? i mean there still needs to be fresh uranium added eventually
flame wars is where we start insulting each other and calling each other out for malicious intentions so unless your very subtle and i'm very dense we are not headed in that direction. assuming it can be made light enough and stay safe enough the concept behind any nuclear powered means of flight is simple(ITS FLOWCHART TIME!)
[Uranium]---applies heat to---->[air, water, or anything that expands rapidly when heated]
and the expanding gasses are directed out the back producing thrust it is the same as the normal jetpack but instead of exhaust its super heated air
i stand next to my normal reactor(listening to it go "click clickclick click") all the time and i'm fine radiation is just a myth
nuclear jet pack sounds perfect lets see unless it ran off depleted cells it should have a very long flight time. what should the altitude performance be like? and how should it be refueled? (canning machine? mfe? put in reactor and breed it?) would the need to protect you from its powerful forces make it decent as a piece of armor? how should its hover mode behave?
the lag i was refering to wasn't the EUnet its when your whole system is power starved the flickering effect you get can even bring you down in ssp
AGAIN its not possible its a limitation of the minecraft engine
and you haven't given us a good reason why this should happen (to encourage lumintator use is not a good reason they are laggy when set up wrong)
a nerf is still a nerf. if you want finite lighting so you can challenge yourself with furnaces, and flint and steel. then come back tell us how much fun you had and if you still want this idea to move forward.
Alblaka is already working on a weapon pack for ic2 or you can use a mining laser
the devs said luminators are already slated for an overhaul. the devs also don't like adding items with out the item being useful(so no placeholders). if you ask me finite torches sound like a pointless nerf there are lots of other ways to make the game harder for yourself but there is no point forcing that desire on others.
directional lighting i believe is limited by the minecraft engine so that is also unlikely to happen
I've fallen out of to many air ships experimenting with zeppelin mod. if it is a true mobile base it must update my spawn as it moves and let me work while it moves (the most practical idea seems to be teleporting structures cause you don't have to turn every thing in to entities)
it will take more than frames what ever makes a true mobile base also has to update my spawn point while on the move
future lesson to all who will redirct people to the other AM addon. when you redirect some one to "origonal advanced machines" include a comment about flaming about where you came from is rude.
