Oh, I should have provided a link...
AFAIK (last time I booted it up and tested it), both I3 and IMC2 work together. i3.c and i3.h are the main files, with a small number of hooks scattered around places like comm.c, and maybe act_wiz.c. Just look for the #ifdef I3 and #ifdef IMC.
My repository is based off the previous 1.9 release, which I then updated to gcc 4.7 and probably ran through indent. I haven't merged your newest bugfixes in yet.
You can compare the changes, as I label all mine with new tags, so I'm a commit ahead of 1.9q3, I think.
Whatever you decide, I highly recommend two things.... use the github thing Kayle set up (or clone mine again), and if you're still going to release old fashioned hand-built zip files, FOR THE LOVE OF ALL THAT IS HOLY, please start adding incremental version numbers into the filenames?
Besides allowing you to easily rebuild a repository when the new thing replaces git in a few years, it makes it easy for a MUD admin to know what bugfixes he needs to grab, since if he's running 1.9.16, and you're at 1.9.27, there are 10 newer files he probably wants to download and paw through.