I installed a Nashbar 1" threaded steerer to 1-1/8" threadless stem adapter on an old Trek so I could use a pair of 31.8 mm handle bars and it's worked well. You can get 1-1/2" to 2" height from one of these but certainly not 3" or 4". An "up angle" (+/- 10°) stem may help but the Technomic is about the only thing that will get you as much rise as you want, other than a new uncut threadless fork.