I believe go-devil actually has an "upgrade kit" for what you are looking for. I'd check with them. I looked at places for a bearing like you are talking about and came up with nothing. If you find one please post because it would be helpful.
If I ask a question, I don't want your opinion. I want facts.
Don't tell me something you think, tell me something you know.
It's easier to say I don't know, than make something up.
Although, being a forum the next guy will know more no matter what.