Hey I found these as possible replacement drive shafts for RCM extended conversions. They are from the Hot Boddies LS10 and measure 83mm x 6mm. The original shaft I got with my RCM kit was a 6mm instead of 5.9mm. I just filed the ball end a small bit and it slipped right in.
http://www.amainhobbies.com/product_...oducts_id/6766
E-CRT.5 Monster - RCM chassis, MM/Medusa 50x3300/3s, truck tires, 1/8 shocks
E-CRT.5 Stock - Sidewinder/4600/2s, buggy tires
E-8ight - Tekin RX8 2000kv/4S
E-8ight T- Tekin RX8 1700kv/5S