My neon-yellow knit hi-viz "safety" gloves from the Dollar Store work great for daytime.
If I can sew some reflective tape on the backs, I'll be set for nighttime signaling as well.
I use road-side mechanics' hi-vis gloves, specifically these:
http://www.drapertools.com/product/27618/Expert-High-Visibility-Mechanics-Gloves-Large.
With these gloves on, arm out-stretched, I rotate the (back of) glove to alternately face forwards and backwards, to effect blinking indicator effect.
It seems to work quite well.
In the past I experimented with using amber/yellow LED blinkies, clipped to the back of my gloves, which I had modified to insert a interuption into the battery supply that was re-connected via a pair of wires connected to some press-stud halves sewn to the thumb and (base of) index finger on my gloves.
Then arm-outstretched with tip of thumb touching base of index finger I have "indicators"
positioned at the furthest separation from the centre-line of the bicycle for best effect
The only problem was that the blinkies made my gloves rather bulky and liable to catch on something.