I do not know a definitive answer to this question, but as there is no other reply so far I will share what I know:
When aiding in Yosemite a fellow climber used nuts for this purpose. You pull back the actual nut so that a wire loop extends behind it. This loop is places around the bolt shaft and can even be tightened. According to him this works fairly well. Still he highly dislikes routes based mainly on bolt aiding and thus only had to use it on certain sections. Due to the weight it is obviously not practicable to use nuts if bolts are your main means of ascent. I once used this solution while freeclimbing a slab that has been cleaned of the single bolt in the middle, but I luckily did not find out whether it would have caught me (to be honest, I was amazed it did not drop from rope drag).
One advice with very limited scope: In Yosemite there is apparently much innovation done in garages, you can find a variety of (sometimes not so)
useful gear. There you can get such bolt hangers, but you are well advice to test them in advance. In a field test 2 out of 4 broke loaded with bodyweight.
I do not know a specific product, but you can use the wires on nuts for occasional use. Homemade solutions are in this case very possible but always dangerous as not normed and thus tested.