I consider RICs pretty light. I have an interesting strap. A friend of mine worked in a factory that made air gascits for the Dimarzio strap, that you pump it up with air. Pretty nice.
I am thinking the best 5 string basses are usually the heaviest ... more mass means better resonance on the low notes ... so when I have back problems I take coral calcium and get a back adjustment ... for me wearing the bass is not a pain ... moving the amps and speakers for a full band ... that is a pain ...
Schlepping the equipment sure was easier 35 years ago! I've been reading the MarkBass thread with interest and an eye to the lighter cabs - my Ampeg is a back-breaker!
American's propensity to overeat and carry extra poundage makes the bass seem all the more heavier - go to the store and pick up a 40lb. bag of salt and realize most all people are at least that much overweight. I'd venture it a safe bet if I lost 80 lbs. my basses wouldn't be hard to wear for hours at all.