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