hhm is in stasis mode because more of the formats need to be discovered and documented in chmspec. If you would like to help with reverse engineering, please let me know of any things you have found. The roadmap is to write lots of tests for chmtests, document what is found by testing against a great many sample files and then start working on hhm. Also, the current code needs to be moved to a CHM creation library such as libmspack or chmlib.
Please contact me if you want your WinHelp/CHM/Help2/etc related project listed here.