What do you want/need from a bug tracking system?
makecheck: Have you spent significant time looking at plug-in schemes, such as those of Trac?  I think you'd be better off writing simple extensions to well-established systems, than making an entire replacement system.  This has two benefits:- People using the established system are more likely to try your add-ons for your unique features.  (Whereas, replacing a system outright is unrealistic in a short timeframe.)- You will have less work to do, as you can focus on the things you've "not seen in other systems", instead of having to do everything.