Try Pinwall.com They sell used motorcycle parts and those on this site have good reviews of their experience. They won't have the parts but have whole rear drive units for a fair price.
Yeah, been there done that.
That was/is still an option but I'm in the middle of a deal through a member here which his drive looks, at least in the pictures, better both on the splines and cosmetically, a bit more $ but way less miles.
The other option, and the reason for the parts question, was my drive is at a former Honda m/c mechanics house (works on m/c on the side now) and he initially told me $150 parts and labor but he needed the money so when I brought the check I looked at the disassembled drive and asked about the left side bearing? He didn't even see that one which cost another $80!!!
WHAT!!! He didn't see it?!?!?!
He called later that night and said now it would be around $330 to rebuild!!! So it's on hold now.
He said his labor is $60 so I figured I could get the parts myself ($180) and it would cost about $240 but I'm not sure if i want this guy working on my bike stuff anymore! Maybe it was just a honest addition mistake (he was figuring it up in his head) cause he seems like a pretty good o' boy, but you never know.
One of my best friends is an unemployed auto line mechanic, and a biker, who has rebuilt many car differentials so when I get this thing back we may look to see if we can rebuild it. Between his expertise, tools (pullers), and my service manual unless there's a special removal/installing tool we cannot get ahold of it shouldn't be that hard to redo.