I can't say for certain but, here are two ideas,
Find a local ski retailer that sells atomic ski boots (oxygen was made by atomic) the mondo size in ski boots should be close enough to know if they can be fitted.
I did that with the Head boots I'm using and it worked great.
Also, Check out the info @
http://bomberonline.com/store/boots/
Let me know, only $50 plus shipping...