The software we use DOES indeed have an optional module which can be purchased, which lets the owner generate custom branded apps for their forum. It'll work with both Android and IOS (Apple) platforms.
It's brand new and for vBulletin version 4.1.2 or higher. (we are currently at 4.1.0) Framer tends to stick with versions that have been "field tested" for at least 6 months, so we don't experience a lot of buggy behavior.
I bet this is something he considers in the future, once we are at 4.1.2+ (and once we have had a chance to test it for a while)
Hopefully he will see this and reply.
Mike