I guy just posted on the CSC RX3 owners group facebook page that he believes the levers from a Suzuki GSXR 600/750/1000 from 2000 may work. The pictures look good and he's ordered a set and will post if they work. there are some good options for fairly inexpensive adjustable, folding short or long options on eBay for about $25USD. I'll be watching his progress and will let the group know. Let me know if anyone else has already tried these!
https://www.facebook.com/groups/CSCRX3OwnersUSA/
Take care and Happy Holiday!