I've also been looking for something better than how SMB mounted mine. I'd like to be able to access the batteries for easy maintenance and change out. Looks like I'm going to have something custom made and I've wondered if a place like Aluminess could fab up something. I'd like to get rid of the plastic marine battery box that SMB uses. Those are really made for an inclosed area.
These style boxes are nice but need to sit on a frame and access through the top. http://www.boatdepot.com/productdetails ... NOCO-HM408
Size may be an issue as well.