New Xtracycle donor frame?
So, I've had my X for going on two years. I use it a lot, and it's really handy, but what drives me crazy is that it's so flexy/noodly. I compensate pretty naturally while I ride, but I notice it a lot pushing it while loaded -- the bike oscillates so much from front to rear, that it wants to lurch out of my hands. It does affect my riding, too... makes it a little less enjoyable and controlled than I would like. I regularly carry passengers, heavy loads, etc. -- nothing too crazy, but often >150 lbs.
When I built the bike up, I used a nice old Interloc cross-country frame. It's a very light, racing-oriented frame made of Reynolds 853 -- probably just over four lbs. I think I had the exact wrong idea; the qualities that make a nice mountain bike (flexy, lightweight steel) seem to cause some ride problems in the cargo world.
So, I'm thinking about trying to find a really beefy aluminum frame, one meant for real Clydesdales, on the supposition that those frames were meant to stay rigid under greater than normal loads. I've been looking at something like the Kona Hoss -- used Hoss frames sometimes show up on eBay for $100-150. Any other suggestions for super beefy mountain bike frames (that don't have crazy dirt jumper geometry)? I don't want to drop crazy money on a Big Dummy -- just want a nice, beat-up old frame to stiffen up my current ride.