Hey, Keith,
I had an idea, in short, look for an Alembic bass with a Geoff Gould carbon fiber/graphite neck/core or look into more efficient braces and straps to better wear the bass without fatigue. It may be useful if you weighed your current basses, and any that your pals might have, while you stand on a scale whilst holding them and comparing them to just what you weigh on the scale, and quantify what is comfortable to you?
Most full/medium-scale series ones that I recall being weighed are about ten pounds, short scale are around eight to nine pounds I think, and for reference a GGi5 was touted around 8 pounds, and that is a bolt on carbon fiber/graphite neck and an laminate top on an alder body. I think.
Also, have you looked into HOW you support your bass when you play, and what other straps and braces, etc., are available to help you play more comfortably? I don't know the scope, myself, of what options there are, but there must be more options than just Levy's and the like.
I dunno if this helps, but I thought I'd raise the Alembic carbon fiber bass option, and put the bug in the Forum's ear about how to better wear an Alembic so as it is a bit more lithe. Cheers.
-Zut
