Run, don't walk to a good skate tech, and have them punch out the area of your boots next to your toes, so the boot touches the sides of your toes as little as possible, if at all! I believe a properly fit and modified skate boot should NOT give you a bunion, or make your existing ones worse. And next time you buy skates, get ones with extra wide toes, from Jackson or Harlick.
Perhaps you can do something similar to ballet slippers?
Also, you might look into a bunion spacer - improvised or purchased, so your big or little toe can't be pushed into the one next to it. Though I guess that only helps the toe itself - not the metatarsal. I looks like that would be true of the bagapads device just discussed too - it at least looks like it might INCREASES the inwards pressure on the metatarsal.
I was told I by Phil of Harlick that I might have a slight bunion, which would make sense since it took me a long time to figure out that boots can be punched - but I'm not letting surgeons anywhere near my feet.