i've had this issue for years. here are some light weight basses i've played.
one of the lightest basses made is the hofner violin bass, regardless of what series. they weigh in at around 5 pounds, often less. they have a 30" scale, lovely deep sound and gloss neck. i really like them, but for me, they proved too uncomfortable for me because of the sharp edges and waist. if you can try one, i definitely would. if you find it uncomfortable, the hofner club bass - again, any series - is lighter than an ibanez mikro, often around 5 to 5 1/2 pounds, also 30" scale. not P or J, but you can't beat the weight. be aware that other brands' violin basses are sometimes around a pound heavier.
i recently got an ibanez GSR100EX mahogany
https://www.sweetwater.com/store/detail/GSR100EXMOL--ibanez-gsr100ex-gio-mahogany-oil
it weighs in at just over 6 pounds - the one with black paint seems to weigh more. it's not short scale - this is the cheapest 34" scale bass, but somehow despite the pain most basses cause me to play, this one is so comfortable that i bought a second one to mod.
one of the board members here has one of the smallguitars.com basses, and he let me play it. so comfortable you wouldn't believe it!
https://www.sweetwater.com/store/detail/TB4PSBG--traveler-guitar-tb-4-p-bass-sunburst
btw, my fender mustang PJ was almost 8 pounds and my jaguar short scale was over 8. if you want to try one of these 30" scale basses, i suggest you buy them somewhere where they'll weigh several for you and send you the lightest. i've owned both, loved them both. and don't forget the cheap squier bass - like a budget mustang. mine was lighter by over a pound than my mustang.
and don't forget the traveler guitar TB-4P. i owned one of those, too. about the same weight as a mikro - from just over 6 to under 7 pounds. i wasn't crazy about the tuners, but they could be replaced. it's more comfortable to me than the mustang or jag ss.
Invalid Link Removed