Sorry, I somehow missed the loft/desk part of the OP. I would still suggest looking at Wal Mart, just read all of the reviews and questions/answers people put on there, they can be very helpful.
Oh, and some bunk beds don't need the bunkie board, just check the website carefully. I know ours from Wal mart didn't need one, but others from Rooms to Go did need them.
One more thing, I really wanted to get a set that could use a real mattress, not one of those tiny thin ones. if that is important to you check the description carefully.