Do you guys do them upon request?
Yes. But they won't be published on the site.
Well, actually, we have one remix on site. The Mario Kart 64 song "End Credits" include a part at the beginning which isn't in the in-game song, but was introduced in an OC remix called "Day's End". It's epic, though, so please don't change it.
Ok sounds good then. Also I heard that MK64 OC remix, right now. It is very epic indeed.