I attached high-reflectivity vinyl strips to a pair of work gloves.
The reflector strips extend all the way around the cuffs, so it's visible front & back when I hold up my arm as a turn signal.
And the vinyl reflective material stays very visible in the rain.
Commercial alternatives: I didn't find any I liked which were reasonably priced. Reflective piping is not sufficient; you can't see it very far. Cloth reflective materials lose reflectivity when wet; they are less visible in the rain when you need them the most. These gloves are close: They have good vinyl reflectors on the backs, but not the front, and are pricey: http://goo.gl/eKCJBL
So I made my own...
Step 1: Parts and Supplies
Get a pair of work gloves with wide cuffs from your favorite store. I like any of these: http://www.harborfreight.com/catalogsearch/result?q=red+work+gloves
An office stapler
Step 2: Assembly
Staple the vinyl strips all the way around the cuffs of each glove, front and back.
For best results, I recommend you staple from the inside-out, so the pointed ends of the staples are outside.
The first time I made these, I stapled from the outside-in. Unfortunately, the points often scratched my wrists or caught my shirts. Not fun.
Step 3: Done
Test them. Get in your car at night, shine the headlamps, and have a friend bike past wearing the gloves. You'll like what you see.
Step 4: Re-do
The gloves typically last me 9 months to a year.
Future enhancement: Even wider reflectors. When these vinyl strips wear out, I am going to replace them with 2" / 50mm wide tape.