Me and the mule are on the same wavelength: The 80's Yamaha BBs are really well built axes, and like all 'vintage' Japanes guitars are WAY underpriced (YES!!) for what you get. I slowly collected all three versions of the BB5000 for a grand total of less than 2 grand, for three neckthru, limited production axes. MIJ, neckthru, great tone.
In the four string BBs, try and find a good 3000 or 3000A: the earlier 1200 and 2000 are fine, but the necks are much fatter than a 3000. The current BB 4- and 6-series reissues are absolute steals, there are NO better basses for under 500 bucks.
Past that, I would never break my 'standard-pickup-size' rule. Most times on cheaper axes, the wood is way better than the electronics. So I always shoot for something where I can drop in EMGs or Barts or Activators or whatever you like. Not worth it to me to do major rout surgery: I stick with axes that use regular P or J or MM, etc., routs. The BBass is a perfect example: All maple, well built for the price, and you could replace the factory pickups with Jazz Bass pickups from anyone you like, if you want to.
LOTS of Ibanez SoundGears out there, and since there are so many different ones, the really good ones are cheaper than you might expect in the used market, and take stock pickup sizes. Squires are great hot-rod subjects. The all-Koa Peavey DynaBass is a set of EMG P/J-BTS Circuit away from being a fabulous neckthru four-string. Lots of guys bought the Toby Pros and replaced the pickups with an original Bart setup from their expensive brothers.
I love stealing an overlooked piece and customizing it. Back in the 80s I bought one of the original Squier reissue P Basses ($179 ! ! ), installed a PJ EMG setup, replaced the chrome hardware with all-Fender gold parts, sold it to a guy for $1500. He STILL plays it and won't sell it back to me. You rarely get that kind of return, but still lots of fun.
J o e y
