Greg : will you please do your recipe magic (and I guess piss a few more people off...) and block the iron duplication via railcraft?
Yeah, due to the easyness of removing Recipes (just a Function with Parameters, which is even integrated in the addCraftingRecipe-Function to even more easyly overwrite Recipes, since 2.73a), one could call it Magic. 
The bug is this : Eloraam's alloy furnaces melt down vanilla iron containing items and give you the iron back. There is no configuration option to change how much iron you get back, nor to disable melting certain items.
Covert Jaguar's Railcraft allows you to make 2 minecarts using 5 steel, or up to 64 track using 6 iron. This means that when you melt down the minecarts or track, you get more iron than you started with.
The Steel Recipe is already fixed (guess, why I allow maceration of Minecarts). Slowpoke once said, in a PM to me, as Part of a Sidenote, that CovertJaguar has nothing against me changing his Recipes (even though I didnt change them for now), so WHEN I do it, then on Railcrafts Side.
I have messaged them both in the Minecraft forums and they both say it's the other's fault.
ELORAAM ANSWERED YOU!?! I'm still waiting for her Reply on MC-Forums, and Slowpoke said (in this Thread), that he would poke her. Now we know, why he is named like that. (Unless Eloraam decided not to answer)
Your crafty code could detect either or both and fix one of them. Virtually all hardcore players who enjoy your mod will be using railcraft and redpower.
I dont fix Alloy Furnace Recipes, until I get permission for Redpower Compatibility (which would result in Electric Alloy Furnaces, Blutricity-EU Converters (if allowed ofcourse) amoung many other things).
Oh god, that'll be the most hilarious prank, for people who start off with that version of GregTech; if that was ever done. XD
But! That prank shouldn't last no longer than a day though; because people would be EXTREMELY pissed that just getting wood planks cost that much to get is completely impossible to continue on. >3>
- Soldjermon
Hrrrm, GREAT IDEA. I will implement said Suggestion of Sengir RIGHT NOW! Muahahahaha!!!
(ofcourse I won't remove the regular Recipes of Planks, so this is just an option I provide)