@Fireblah: Amaron sells a VRLA battery which is dimensionally very close to the Yuasa YZ10S battery to the battery of my R1 and the '10 Blade. I think it's a 9 Ah battery, which should do just fine.
As for the battery going flat, my R1's battery has been totally drained at least 10 times in these last 2.5 years. Thrice due to me not running the bike, and remaining due to innumerable compression tests on the engine. Only once due to the fans running continuously in the intense summer heat while I was on a 1800 km ride
The battery still holds charge after all these days, and misuse.