I have run across a number of people who want a bigger motor on the Taig mill. The main problem with this is that big motors are usually heavy, and hanging a lot of weight on the side of the Taig column could cause problems. Recently, I found myself in a similar situation, and my solution should be useful for those who wish to hang a heavy motor on the taig. I don't recommend exceeding the limits of your machine, but this technique could theoretically be used to put something like a 5HP motor on the Taig.
These photos pretty much show the solution: Use as heavy a motor as you want, and use a pulley and counterweight to balance out the weight of the motor. (The counterweight in this photo is hidden behind the lathe stand). In my case, this big old 15 pound motor was only 1/4 HP and it was the only thing I had to drive my homemade mill. Before I mounted the motor on anything, I lifted it up and down by hand to see if the counterweight was sufficient.
I must repeat that there is nothing to be gained by putting a motor an a machine that is too powerful for it. A judicious application of common sense is needed. That said, There are some pretty exciting possibilities here. The Taig could be outfitted with a vfd (Variable Frequency drive), or a slower speed induction motor, or even a compressed air motor. One last safety caution: Make sure that your pulley arrangement will not come down.