Hey, the guy is just asking! Sometimes the stupidest ideas lead to brilliance (I'm not saying your idea is stupid, I'm just saying).
1. DL1000 wet weight = 523 lbf
2. Rider weight = 250 lbf
3. Passenger weight = 120 lbf (hey, that's what she told me)
4. Nice assortment of farkles, unpacked = 100 lbf
5. Slope angle of the hole you managed to get your front end stuck in = 5 degrees
6. Drive sprocket on the Super Deluxe V-Strom Reverse Contraption = 3" diameter (about the same size as the drive sprocket from the engine)
Shaft torque requirement for your motor will be 328 in*lbf, just to keep it static on the 5 degrees. The motor will be able to move the bike on any slope less than 5 degrees, and anything more you'll be doing the reverse shuffle with your feet to help it out.
However, sprockets can't engage and actually put power to a chain that isn't wrapped at least 120 degrees or so around the sprocket, and that's with serious tension and/or idler sprockets. The rollers want to climb out of the valleys of the sprocket when power is applied, and there's nothing stopping them with small amount of engagement. You'd need a couple of idler gears and a lot longer chain to allow it to snake its way around the reverse sprocket.
You'd be better off putting a friction wheel against the back tire. Your torque requirement would go way down. The same 3" drive (now a rubber wheel rather than a sprocket) would require about 130 in*lbf.
I think a 623-pound bike would benefit from reverse also. Maybe not to the extent of an 800-pound bike, but tell that to your 120-pound passenger as she's pushing on the front of the bike while your 250 pounds is steering it.
Edit (disclaimer): I doubt this info will ever be used, but if it is please let me know. If you're gonna use it, you should understand and take responsibility for the calculations. Therefore, make sure you either work through them yourself and verify my results or inquire how I did it.