*bump* or is this too classified? 
Or a too new feature?
I looked into the code and its fairly simple:
No You can not add a custom Profile, it is actually hardcoded into the mod.
Even if you change the Classic XML File you can only change recipes with it that is the limitation from that point.
No nuclear Jetpack. I doubt that they ever going to implement that since its not their way to implement things that way anymore.
for items yes, for recipes its correct, for textures that seems to be hardcoded too
Once again Speiger has looked but failed to observe. A little like me and the forum 
First, you can make your own profiles! Just because IC2 happens to come with only two doesn't mean it's only limited to two. Any profile.xml files in a folder or a zip within an ic2_profiles folder in the root of your minecraft instance (ie the same place where mods, config, logs, etc. is in) will be loaded by IC2. Every file mentioned by the profile is positioned relatively to the profile.xml, so you can pick between organising everything nicely in directories and dumping it all into the root.
Second, a full profile XML is (currently) defined as
<profile>
<!-- Profile name, used to tell different profiles apart -->
<!-- Case intensively matched so aMaZiNg PrOfIlE is the same as this -->
<name>Amazing Profile</name>
<!-- Texture additions/changes, used to effectively shim a default extra resource pack -->
<!-- Can be three different things:
NEW which applies the normal experimental textures onto IC2
OLD which applies the old textures onto IC2
Path to additional assets which can be applied to any mod (just like a resource pack)
From a resource pack's perspective the path points to subdirectories of the assets folder -->
<textures>NEW</textures>
<!-- Mechanics style, influencing things like energy storage, tiering and cells mechanics -->
<!-- Can be either NEW for normal IC2, OLD for classic IC2 or BOTH for everything -->
<style type="OLD" />
<!-- Individual JEI overrides for blocks, used to mask things -->
<blocks>
<!-- List of blocks to show in JEI, regardless of the style settings -->
<whitelist>
<!-- Blocks are listed via stack tags: -->
<!-- Stacks are defined either via combined which is the IC2 ini format -->
<stack combined="ic2:te#electric_furnace" />
<!-- Or split id, meta and NBT: -->
<stack id="ic2:cable" meta="0" nbt="{type:0b, insulation: 1b}" />
</whitelist>
<!-- List of blocks to hide in JEI, regardless of the style settings -->
<blacklist>
<!-- Format matches that of whitelist -->
</blacklist>
</blocks>
<!-- Individual JEI overrides for items, used to mask things -->
<items>
<!-- Format matches that of blocks -->
</items>
<!-- Changes to recipes that use the vanilla crafting table -->
<crafting>
<!-- Changes to shaped IC2 crafting recipes -->
<shaped>
<!-- All tags are optional -->
<!-- Use the recipe changes from another profile -->
<!-- Can only extend from a single profile (right now at least) -->
<extend profile="profile name" />
<!-- Extra shaped crafting recipes to add to those already loaded -->
<additions>
<!-- Changes can be file nodes which load additions from the given ini file: -->
<file path="path/to/file.ini" />
<file path="path/to/file2.ini" />
<!-- And/or folder nodes which load all ini files in the given directory: -->
<folder path="path/to" />
</additions>
<!-- Shaped crafting recipes to be removed from those IC2 would otherwise add -->
<!-- Can be done via the config, but that removes from all crafting/machine outputs -->
<removals>
<!-- Changes can be any of... -->
<!-- Stack nodes which remove any recipe with that output -->
<stack id="minecraft:stone" meta="5">
<!-- Ore dictionary nodes which remove any recipe with the given ore dictionary tag -->
<ore_dict tag="oreStone" />
<!-- File nodes of specific recipes to remove -->
<file path="path/to/file.ini" />
<!-- Folder nodes of files with specific recipes to remove -->
<folder path="path/to" />
</removals>
<!-- Shaped crafting recipes to be used instead of IC2's defaults -->
<!-- Cannot be used in conjunction with any other extend/additions/removals tag -->
<replacements>
<!-- Format matches that of additions -->
<!-- Note: Leaving an empty replacements tag will result in no recipes being added -->
</replacements>
</shaped>
<!-- Changes to shapeless IC2 crafting recipes -->
<shapeless>
<!-- Format matches that of shaped recipes -->
</shapeless>
</crafting>
<!-- Changes to IC2's furnace recipes -->
<furnace>
<!-- Format matches that of shaped recipes -->
</furnace>
<!-- Changes to IC2's macerator recipes -->
<macerator>
<!-- Format matches that of shaped recipes -->
</macerator>
<!-- Changes to IC2's compressor recipes -->
<compressor>
<!-- Format matches that of shaped recipes -->
</compressor>
<!-- Changes to IC2's extractor recipes -->
<extractor>
<!-- Format matches that of shaped recipes -->
</extractor>
<!-- Changes to IC2's ore washing recipes -->
<ore_washer>
<!-- Format matches that of shaped recipes -->
</ore_washer>
<!-- Changes to IC2's thermal centrifuge recipes -->
<thermal_centrifuge>
<!-- Format matches that of shaped recipes -->
</thermal_centrifuge>
<!-- Changes to IC2's blast furnace recipes -->
<blast_furnace>
<!-- Format matches that of shaped recipes -->
</blast_furnace>
<!-- Changes to IC2's block cutting machine recipes -->
<block_cutter>
<!-- Format matches that of shaped recipes -->
</block_cutter>
<!-- Changes to IC2's recipes in the metal former -->
<metal_former>
<!-- Changes to IC2's cutting mode metal former recipes -->
<cutting>
<!-- Format matches that of shaped recipes -->
</cutting>
<!-- Changes to IC2's extruding mode metal former recipes -->
<extruding>
<!-- Format matches that of shaped recipes -->
</extruding>
<!-- Changes to IC2's rolling mode metal former recipes -->
<rolling>
<!-- Format matches that of shaped recipes -->
</rolling>
</metal_former>
</profile>All tags except name, style and extension can be repeated as many times as desired, and only name is technically required to define a valid profile (style and textures both default to NEW).
Additional profiles can be selected within the main IC2 config by their name as it describes (which you'll remember is case insensitive). Duplicate profile names will log a warning and continue to use the first profile registered with the name. If the profile in the config can't be found it will log a warning with all the profiles it has managed to load and will continue using the default (Experimental).
It needs to be a mod/addon, profiles don't really add new content afaik
