My sis is completely in love with Sergio Pizzorno. I have no interest in the bloke, but his guitar looks pretty funky. But it's not anywhere! Not in the Rickenbacker website (only the schematics), not GAK, not Musicians Friend, where would I be able to purchase/try one out?

Thanks in advance...
that's a pretty awesome guitar, I dig how it's got the backer bass body.

According to this rickenbacker forum, it's been discontinued for quite some time.

try ebay.
"There he goes. One of God's own prototypes. Some kind of high powered mutant never even considered for mass production. Too weird to live, and too rare to die."-Duke
if possible, you should check out Denmark street in London (around soho). I'm sure i saw one in one of the shops a few weeks ago, might take hours to find though - just finding which shop it was will be tricky. wasn't cheap i have to add.
Rig Winter 2017:

Fender Jazzmaster/Yamaha SG1000
Boss TU-3, DS-2, CS-3, EHX small stone, Danelectro delay
Laney VC30-112 with G12H30 speaker, or Session Rockette 30 for smaller gigs
Elixir Nanoweb 11-49 strings, Dunlop Jazz III XL picks
Shure SM57 mic in front of the amp