If you want a nice amiga you would keep the stuff you have. If you can't fix the motherboard, look for another one or consider amiga center france for repairs. Your expansion hardware is hard to come by and expensive, keep it. ( you said you got a great deal on it ).
I bought an a3000 motherboard from ebay for $100. It came with the daughterboard. The guy who sold it basically seperated his 3000 into 100 pieces and sold it on ebay individually and he is not the first to do that.
You would do best to keep what you have and either have your stuff repaired or buy a new motherboard.
If you still want to sell, let me know, i'm in the market for a new video card.