I use the RX inserts with a pair of Rudy Project cycling glasses. They work well, although they take a bit of getting used to - for some reason (probably because the lens is so close to the eye) everything looks quite different when you wear them in place of normal glasses, but after 5 minutes or so it feels normal.

You can get your own prescription put into the inserts - I used an online service, which was far cheaper than the high street, although I don't know if they do bifocals.