There's several I regret selling but having only so much space for storage I had to sell them to move on to better things. A few regrets include My reverse 3 wheel tandem (2 wheel in front, took up 90% of my shed), Two other tandems (again not space savers), my tadpole recumbent (definately not a space saver), My Hutch Judge (go price parts), My first Rat Rod I built here (was hard up for cash), few older vintage bikes, several nice mint Schwinn road bikes (I'm short), and the first custom frame chopper that I built (was sick of my friend bugging me).... just to name a few. If I kept ALL the bikes I wanted to I'd need a building the size of Wal-mart to keep them all.
But looking back I always got a good price or a good trade so I can't complain too much. If you never sold your toys you never get new toys. I just always keep the BEST toys. :mrgreen: till I find one better. :lol: