I think the single task I've spent the longest on so far is this mounting bracket I made out of an old 10-speed bike frame (seat/chain stays & front fork):
The pic doesn't really show how 3-D is is. It's a 3-point mount: 2 on the firewall, and 1 on the strut tower. And it had to go around/avoid a bunch of stuff, and sit fairly close over the transaxle.
Here it is with the component platform finally attached. Soon the remaining bits 'n' pieces will be attached to the piece of lexan.
Today's task was making up brackets & a tray which will hold 3 used 12v 7AH alarm system batts which will make up the 12v accessory power. The plastic used for the tray was the top of a used 45 gallon barrel (cut the top off to make a rain barrel). Heated it in the oven to make it pliable, then formed the edges. Not a very professional result. Yes it's fugly, but it works, so it will stay.
I'm also actively shopping for a DC-DC converter. Seems like there's 48v stuff available for $20-30 including shipping. We'll need one to keep the relatively small 12v batts alive under heavy loads (lights/wipers etc).