Yes, you can install it inside any directory you wish. The challenge you may face is with the log in. Members will need to also log into vshare to comment on videos, rate them, etc. This means they will have two log ins - one user name/pass to log into your members area, and one to log into vshare. That is, unless you are able to build a bridge that will connect the two with the same user/pass. Hopefully that makes sense and you can understand what I'm saying.

As for templates, I would suggest that you ask grynmoors about it.