Millhouse, if you live near a good electronics shop or auto supply shop (somewhere like Jaycar is good) have a look for some terminal block strip, same stuff as is used in electrical wiring and lights in houses. Looks something like this, comes in various sizes and also in ceramic if you want heavy duty. You can cut one strip and use half each for + and -.
http://www.jaycar.com.au/products_up...Large_1227.jpg
If you want something a bit nicer looking, use one of these
http://www.jaycar.com.au/products_up...tLarge_672.jpg
They are pretty but a bit more expensive. You will need one strip/block for +12v and one for -12v so colour code them black and red accordingly. If you go with the simple plastic terminal strip, cut a long piece in half and this gives you enough to do your + and - rail. You put your battery wire (use good heavy gauge wire though, and 12v rated, not household wiring as it won't last. The type used for large spotlights or similar would be good, not sure what gauge this would be off hand, I pick wire based on the size of it, you want about 5mm diameter of copper in the cable) into one side of the first clip on the strip and then use some heavy copper wire (even a coat hanger wire works but copper is better) and make wire U shaped "jumpers" (like this UUUU) to join all the seperate terminals inside the block together, so any one has voltage. Do this up one side, then tighten the screws, this should leave you with the opposite side free to screw in all your outputs. Do the same with the second block for -12v and you are done. Mount this in a plastic project box to keep it waterproof if you like, but put it somehwere you can get to it easilly. It is best to fuse each thing coming out, that way you can wire up a small device with a small fuse and larger fuses for bigger devices. Use decent crimps to hook it up to the battery. If you don't have the gear lying around, measure the lengths of wire you need and ask an auto electrician to fit a terminal on each end for the battery and the block. Most places, including Jaycar, will sell the wire by the metre.
Sorry but I have not yet done this to my Landy so I have no pix of one done up yet, but hopefully you het the idea. Plastic strips are a couple of dollars each, the gold fancy blocks with only 4 outputs are about $13, so weigh up time versus cost and pick the one thats best for you. Always go the gold fancy ones if you are putting this under the bonnet or anywhere visible, they look better and last longer, but nothing beats having 10 power outputs hidden under the dash.

