Hey! I've got the manual for the RTR, although I think I have the PRO version. (chassis is exactly 12" long if anyone can confirm this; my chassis fits a standard servo) The front dogbone is listed as just 40920, and so is the rear one. They must come in a pack of two.
The manual says as follows:
40920 CENTER DRIVE SHAFTS, 60/82.5mm [retail] $15.95
The mesurements seem right after trying to bend the rear one back.
Found them here, about 1/4 way down -
http://www.ofna.com/parts.php?start=3600
But nowhere else.
I'll shoot OFNA an email, along with my lhs