Hi there!
I got an awesome deal online for Joey's BBB. I too started the search early...I ended up getting a very Pottery Barn-looking bed at Kmart.com. It is a twin, and we put the siderails on to make it feel crib-like. To make it additionally cozy, we laid pillows along the rails. He picked out his sheets and pillow.
We also bought a new house and put him right into the BBB at that time. He was SOOOO excited to have a new house, a new room, AND a big boy bed that the transition was no trouble at all. I think it depends on your LO's personality. Joey LOVES having his own territory, so this worked well for him. He's also been a great sleeper, so that helped too.
Also, not sure where you are, but when we decided to buy our house, we first brought Joey back to look at it with the realtor, then I brought him during the home inspection, and he was here for moving day and helped "decide" where things would go. Again, it totally depends on the kid, but he was really psyched to be involved and the BBB just came with the new house as far as he was concerned.
P.S.-- Just wanted to add, he was about 30 months at that time.