I have built and tried about every tapping fixture in existance. Jeff's works well but I have to make bushings for it for different taps.
This is the simplest thing I've ever seen: http://www.sherline.com/tip7.htm
Not a bad idea, but for linner locks I like my coardless drill, turn the torqe all the way down, hold the piece with one hand and drill with the other. Use slow speed and when the tap bottoms out it take the linner out of my hand and I know it's time to stop tapping So far haven't broke one yet like that and it's a lot eaiser to get it square than with a T handle or such.
For other projects though, that looks like a great idea, I've been turning the chuck by hand.