Just thought I would give a preliminary report on the inexpensive quill to threadless stem adapter I mentioned in another thread.
I ordered this part from chucksbikes.com for $5! It is very nicely finished and fit perfectly. The $8 Titec threadless stem, 100 mm, zero degree rise, also fits perfectly. The stem has a two screw handlebar clamp so you don't have to strip the bar to install it. Both these parts are for 1 1/8" steerer tubes, common on mtb and many hybrids. If you have been wanting to try some of those nifty threadless stems but are stuck with a quill, this is a way to try them out. Both parts, plus shipping, came to $19. If you prefer some adjustability, Nashbar has an adjustable stem by Zoom in 3 lengths that would work on this adapter.