http://www.motobattbatteries.com/about
I just ordered an AGM replacement for my Buell. They're more than a wal-mart battery, but have a 2 year warranty, free shipping, and are AGM vs traditional wet acid, so I thought I'd give it a try. They are also an Amazon Prime seller, if you do that sort of thing. I'm not sure about their "more lead" sales pitch, but it sure sounds good :) I think that surface area would matter more than the actual amount...
Anyway, I just thought I'd throw a battery supplier out there for anyone else interested. I'll let you know how it goes.
I checked it out and sounds good. I tried e-bay and I can only see it being supplied from Europe for the MTBX14AU which is the size Motobatt website says is for our V's. Price shipped to Canada is $88.05 CND + $7.51 for shipping. Pretty cheap for an AGM battery. Also it has 4 posts so it is easier to tap off of the battery for more power later.
http://www.motobattbatteries.com/motobatt-mbtx14au.html
Seems to be available domestically directly from the manufacturer. Amazon too ( http://www.amazon.com/MotoBatt-MBTX14AU-Factory-Activated-QuadFlex/dp/B003YMTMI2/ref=sr_1_1?ie=UTF8&qid=1396889464&sr=8-1&keywords=MBTX14AU )
I had one in the XZ400. Cranked better than lead/acid and kept its charge way longer. Build quality good, but the terminals kept coming loose I kept meaning to hit them with some locktite, but unsure what that would do to conductivity.