The Clie SDK seems to be geared towards people using CodeWarrior. Has anyone managed to get it to work using GCC?

I think it should work fine with little or no modification. I've gotten it to work within OnBoardC, which is surely a more limited environment than GCC. Start with a basic Palm app that compiles in GCC and start by including "SonyCLIE.h". If that fails to compile, go through the two .h files that it includes and the .h files that they include and comment out the ones you won't use (there is one for jog dial support, one for the extra sound hardware, one for HiRes, etc.) and modify the rest to compile in your environment. Once that works, add an initializing and clean up function to locate and possibly load the library and then clean it up. Just steal the code directly from Sony's Programmers Companion.