I believe that last "official" Kickstart ROM was 3.2 and it was only in the Walker and never released to the public. The 3.2 rom was 1 1MB chip rather than 2 512k chips and had support for 1 extra custom chip (forgot the name) and had a slight fix for larger hard drives (4gb partitions and 9GB overall size) and an improved Setpatch, as well as a cdrom file system (borrowed and modified from cd32) and the frame work for a future super IO type setup. I think after all was said and done only 16k was left to load anything from software (rom space wise). Feel free to correct me if I am a bit off but that is what I recall.
