I did read in one of the car magazines I subscribe to that BMW was seriously considering a 'long wheelbase' Mini...I can't remember the details but IF it makes it into production probably won't be earlier than an '09 model. Either way, it's comfortable enough for two average-sized adults (5'10" guy/5'4" girl). More than that and you're pushing it. But here's a link with some info about it: http://www.motoringfile.com/2003/06/01/TheLatestOnThe4DoorMINI However, what I think is far more promising for the U.S. market is the Mini 4x4: http://www.autoexpress.co.uk/news/autoexpressnews/203775/mini.html
I loved my 2 MINI's. The did eventually get to be too small. Once my kids reached 7 & 5 we were out of room.