Unfortunately I think I know the answer to this, hoping someone know something I don't.
I've got multisite set up as well as domain mapping. I don't have a main site domain name (hoping I won't have to) but I do have an IP address (http://188.8.131.52). I set up my multisite as subfolders instead of subdomains. I've got a couple domains set up and they are going to the correct blog site (http://bikesantaclarita.com and http://cresttocoast.com).
I would like to mask these domains but all the documentation I've found is by using CNAMEs to point to the subdomains. This leads me to believe I cannot mask using subfolders.
If this is the case, how can I change my network to subdomains? Since I don't have any content I'm more than happy to delete the sites and recreate as subdomains, if that's possible.