[quote name='Grahambythesea' timestamp='1452355574' post='2949220']
GAK & Richtone both have them, I don't think they ae rare, they seem to come up on eBay quite often. I have played one and don't think they are anything out of the ordinary, if anything they are a bit prone to neck dive.
[/quote]
The OP is asking about the Gibson Les Paul Signature, not the Jack Casady. The Gibson LPS was only made from 1973-79 and is indeed rare and rather expensive whenever it appears on eBay or whatever.
I had a Jack Casady and I could see myself going back to one in the future - they're so lightweight but sound really good to me. To be fair I did fit Ultralite tuners to it (one of the press fit bushings of the original tuners was coming out of the face of the headstock under string tension, and it bugged the neat freak in me ) but it didn't neck dive with me.
RE: the LPS, I've never had the pleasure of playing one so I can't comment on them much. Lots of info at [url="http://www.flyguitars.com/gibson/bass/LesPaulSignatureBass.php"]http://www.flyguitar...gnatureBass.php[/url]
Noteworthy that Jack Casady had one, and when he came to help design his signature model, he cited the pickup of the original as a weakness and sought to design a better one with Epiphone ("I loved the bass but found the pickup to be deficient.")
Apart from that I got nothing, including the three grand minimum budget I'd need to buy a Gibson LPS bass