software

Can it be Done? Can you pair a full shred with a '59 sothat you could sound like motorhead Or Led Zeppelin? Will it work, or will my geetar sound like someone dropping rocks down a laundry chute?

Most likely, it'd lose some of the crunchiness and tightness. You'd get a pretty aggressive PAF, with less midscoop than a stock '59. Both use Alnico 5 right? Maybe to 'tame' it down you could try an Alnico 2 magnet?
I want to make a hybrid out of a FullShred and Custom. A tight monster, with balls. I can't wait to get started.

Here's an Idea, take a strat, put in a '59, a custom, and a FS. Tight, balsy, and with rediculous vintage PAF tones. Hmm

That's my combo.

Combined they have an interesting vibe (hard to describe and quite frankly I don't use it too often), and my experience I'd say for:

Motorhead: Use the Full Shred and roll abck the tone a little and beef up the mids and bass (amp wise)

Zepp ... I've pretty much used the '59 and sometimes combined the '59 and FS to get a cleaner sound