Yeah, we use their batteries in our forklifts at work as well as some other battery operated equipment. Of course these are not the AGM type batteries, but with regular maintenance, they hold up pretty good. Not the same as your automotive type battery, but I have heard of them.

Here is the link to their sales info on the "Intimidator" battery.
http://www.dekabatteries.com/assets/base/1721IntimidatorCompleteline.pdf

Here is their website: http://www.dekabatteries.com/

I believe that the group 34 is the largest battery that will fit. I think the last time I bought one for my truck, it was a group 34 and it has more cold cranking amps and the largest that would fit without modifications. Good luck with choosing a battery and I would like to know if you get this one how it works out for you. I've got to get one for the wife's 4Runner soon.
Here is Deka's page for the group 34 intimidator http://www.dekabatteries.com/default.aspx?pageid=163