Just came across a post from Channel 9 from back in October of 2005 which should be of interest to all BizTalk developers. It is a conversaton with members of the BizTalk Mapper development team about prototype improvements to the mapper which they had. The conversation runs on a bit, with introductions of lots of folks and such, so if you want to jump to the meat of the subject jump to time index 9:40 and watch the magic.
Unfortunately it does not appear that this has made the cut for BizTalk Server 2006 R2, which means we'll have to wait for the 2008 drop to get these toys. *sigh*