Obviously the easiest solution is having a pre-amp with speaker simulation, and feeding that over a floormonitor. But I can image you'd rather just use a tubeamp, which makes sense in some ways. I wouldn't point the amps towards the wall or something, unless some of the miked signal is going to be amplified through the monitors. Cause in the end, most guitarplayers want the guitar to be loud enough to have the extra sustain that comes with volume. I think the best way to solve the problem is to fit some beamblockers and to point the amp towards your ears (put it on a flightcase, angle it, whatever it takes), if possible on the side of the stage. This way the guitar will be plenty loud without deafening the audience or bandmembers.
I've tried most of those things. In the beginning the amp was standing on the floor behind me. Never again. You'll dial in too much treble resulting in a harsh sound which is also too loud for the soundguy (but you'll hear almost no guitar...). Getting tired of that approach I've tried a few modeling devices amplified through floormonitors. Ideal for the soundguy and the stagevolume can be loud enough, but I found that modeling took me too much tweaking. Now I'm doing the amp-aimed-at-ear-thing, and it works great.
