Used to be a lot of info at RaBB, now known as dbc:
Forum: Amplification / Pickups / Mics / Recording | www.DoubleBassChat.com Place is sadly a ghost-town now.
+1 to Mr Bonny's advice. GK works for a lot of RaB/PsychoB players. However, as he also said — there are no hard'n'fast rules ... Some guys or gals like a typical 8x10 rig, some are into fEearful cabs with a GenzBenz, others are into GK with a 4x10, yet others still are into an Aguilar 4x12 rig with matching Aguilar head, some swear by their Mesa Boogie...
Check out your favourite bands, what are the bass players in those bands using?
Check out (some info may have changed)...
Mark Robertson, Legendary Shack Shakers — GenzBenz [EDIT: Using Greenboy-design cabs he builds himself; also a TBer, Dukeorock (thanks to Rebop & DukeLeJeune)]
Eve Hell, Eve Hell and the Razors - Mesa, IIRC
Jimbo, Reverend Horton Heat - Ampeg switched to GK
Nigel Lewis/Hendrik Corleone, formerly/currently with the Meteors
Eric Haamers, Batmobile
Geoff Firebaugh, BR549/Hillbilly Casino/other bands —
Fender TB1200 8x10 Pro (not sure if he's still using Fender, but you could PM him, he's on TB) [EDIT: GK 1001RBII with a Greenboy cabs fEARful 1515/66/1 and 12/6/1cube (update courtesy Rebop)]
Kim Nekroman, Nekromantix [EDIT: GK 1001RBII with the GK 4x12 neo cabs (update courtesy Rebop)]
Patty Day, Horrorpops
Djordje Stijepovic
Scott Owen, Living End
Brandy Bones/sCare-oline, Big John Bates
Slim Perkins, Tremors – GK
Thomas Lorioux, Surf Rats, Frantic Flintstones, Kings of Nuthin' etc — Ashdown
etc...
Do your homework and you should land something close to what you want/need without having to get on the E-ticket ride "find-my-sound Merry-go-round" (E-ticket, ie "E"xpensive, constantly buying/selling gear in search of...).
Also, there's a lot of misinformation I've seen on the psychobilly forums about "what you need" — 15"/18" speakers, steel strings & mag pickups and then slap 'til your fingers are a bloody pulp...

. Helck, there's a lot of misinformation on TB, too...
Do your homework, then forge your own path to find what works for you.
BTW, great new avatar.