I've played this game on and off for the past 14 years, and almost every time I have wished for units to fill certain niches: Amphibious APC's being the most desired. I know modding is possible, thanks to the Carnage mod on Moddb, but I have no idea how to do it. At the least, an amphibious constructible that can mount unit transport modules would be all I want, just to make low TL water maps more exciting.

Does anyone have any idea on how to begin modding KKND2?

I found this mod for KKND2, maybe you can send a message to its creator?

http://www.moddb.com/mods/kknd2-carnage

The original game is not realy moddable - as the content files are encrypted and all relevant stuff is hardcoded into the executable (which is also crypted, depending on the release). However if you are skilled with hex editing stuff, you could move the unit tables etc to the fileend and use these to mod stuff (its basicaly what the carnage mod does).