Mike, I fully sympathize (so fully, this could be a long post 🙂 ).
I don’t know a few things, like whether your band has gone for the Bose or some other PA + monitors, if you use a soundman, how big the gigs are etc, please come back in with any further info. Here are a few general points though:
Ask your drummer if he’s happy. A good drummer likes to hear a good bassist properly – on stage. Chances may be that another band member thinks the same way as you. Check into “The Bottom Line” forum and perhaps search the archives. A lot of better-payed and (frankly) plain-better bassists than me have discussed this topic. I have to say, most of them are like you and dislike the “PA + mons” approach. I’m even more extreme; for a medium-size venue (up to 250 capacity) I prefer to keep the bass amplification completely away from the PA. It annoys a sounman (he has to work out levels with me, then “trust” 😯 me to stick to them), but here’s why:
A lot of musicians and soundmen don’t know this, but bass frequencies are completely monoaural to Joe Punter. They don’t judge bass as ‘left/right’ – it just comes out from the front and up their trousers. A lot of house PA isn’t really stereo anyway. Secondly, bass doesn’t suffer anything like the absorption-from-bodies that mid-upper (guitar, vocals, cymbals) freqs do. Thirdly, most GP speakers have absolutely pathetic falloffs below 50Hz and really don’t cut much mustard below 100Hz. That’s why your monitors sound fine enough to everyone but you (and maybe that drummer).
For all these reasons, I prefer to let my amp/cab sit behind me, angled slightly at the drummer and honk out into the auditorium. It bugs the soundman, though.
OK, assuming no-one wants you dragging your head and 2×15″ back on stage, then. Finding a good combo with DI out is one possible solution. The other (and I have one of these – tres good) is the Nobels 4-splitter. The four-splitter isn’t a Swiss knife for the Rabbi, it’s quite a handy little (active, 9V supply) box the size of a cig-pack. Bass plugs into input, giving four, balanced, low-impedance outputs. (1) to stage amp, (2) to tuner, (3) to PA, (4) to FOH or powered monitor or separate FX so you have wet and dry bass etc etc. It’s not noisy, either. I first tested it between a passive Jazz and a valve amp, resting the Nobels on a (switched on) PC next to the monitor. For the hell of it, I put the room lights on, too. With this, or some A_B_Y type pedal, you can use an amp onstage at just enough level for you and the drummer to be happy, without upsetting the poor old fader-slider.
I may be barking up the wrong tree, though. Let me know if none of this helps. http://www.nobels.com