QUOTE(Dman11 @ Jun 3 2011, 01:38 PM)

I know I could simply go online and figure this out for myself, but can custom forge maps be hosted on XLink Kai?
Yes.
Also, if you can get someone to get their hands on the usermap, then they can upload it to the internet and you can download it and put it on your HDD. That's how most people used to transfer usermap mods for Halo 3 because they didn't want to risk getting fileshare banned. It would be a lot more of a hassle, though.