Perhaps poesy rings? You might have to buy two sets and wind up with a spare for him. Try sapphire lane dot com and look at the I am His rings... This was the only thing that came to mind when I saw your query. Hope it helps.
PyramidCollection dot com has always been a good site for rings and things. For me, anyway. Not necessarily for what your looking for specifically, but they engrave rings and such, and they have amazing designs. Good luck :)