I threw together a battery hold down for my Optima the other day and took some decent step by steps. This batt is mounted behind my p***enger seat, the hold down needs to be finished a bit more as its still rough, I wanted to get something done quick so I could put it in but its not bad for an hours worth of work. Once I am happy with it ill take it out and grind/sand/file some to get it looking a bit better.
About an hour actually, plasma cutters make things go alot quicker. I spent some time trying to figure out how to "skeletonize" the frame like I did but couldn't come up with a great idea so I did it freehand. That's the battery bracket with a quick coat of black. It's actually back about 15 feet, just a weird angle/pic.
I will probably be making a version 2, probably holes in the center instead of a skeleton. Truth be told I wasn't going for a maltese cross look just something that could grab all 4 sides so I will experiment a bit more before I settle on a design.