Hi Joe. I think there’s at least one person on our forums who writes original instrumentals, but I can’t remember who it is! I even used a couple of his tracks for some older videos. I’m in the process of searching for them, so hopefully I’ll find them and get his name/usename, then send it to you. Maybe we’ll get lucky and he’ll see this thread and chime in!
Edit: Found him! It may not be exactly what you’re looking for, but it might be worth checking out:
http://unicyclist.com/forums/showpost.php?p=1179253&postcount=1
I’m also wondering if the thousands of youtube songs in their “audioswap” library might be ok to use. There are actually some really decent songs and instrumentals there.