I've made one, so far. It's not completely done yet - needs some paint - and I already have the idea for the other tap, just gathering parts now.
The ideas I used came from my username, with one handle representing the golf side and the other representing the motorcycle side. The golf side is a real golf ball and on a "tee" made of machine aluminum. The other side will be a motorcycle grip and brake lever (got this idea after seeing a picture of a similar one).
Will post pics when they're done.
Edit - if you're using metal, of course you can machine the threads into your base, but if you're using wood you can buy the inserts online and maybe a hardware store (I picked up a few at Lowes).