If you mean this project, yes its pretty much on hold, mainly due to a lack of money, but partially because of a lack of motivation. That aside its boiled down to getting an input device, a couple adapters, and something to carry everything in. Sounds simple but its a couple hundred dollars more than I have to spend.

Back to your problem. You can probably make cables, but I don't know that it would be worth it. All data interfaces have a distance limitation, with some of the parts in laptops I suspect its around a foot. If you want to have the hard drive mounted away from the main system, I'd get a bus powered Firewire to 2.5" drive enclosures and use those in place of homebrew cables. You can do something similar with the optical drive, but you'll want a 3.5" or 5.25" enclosure and a slimline CD to Desktop IDE adapter.

Making your own battery cable is less of a problem - power isn't as picky as data lines.

As for mountings/shock protection/etc, someone else can take a stab at that one. I haven't gotten that far.

Anyways good luck, you'll probably need it.