I made a truing stand out of an old fork. I set it in a brick with some mortor and then clamp the brick onto my desk if I need some more stability. I took an old spoke and cut it in two and rubber band the two peices onto the fork arms at the hight of the rim for probes.
For doing a back wheel I have to bend it out a bit, which means that the wheel doesn't run exactly down the middle, so I have to do some measuring with a plumb to make sure I don't dish the wheel accidently, but other than that it works great.