Yeah, i personally havent, but the LFS i work for does this. We design, build and maintain aquariums all over Yorkshire. It is also becoming far more popular... I've only ever helped out once but it was ace, we had to install a 10foot long marine tank, by 3' wide by 4' tall. It was wicked. There is a lot of interest, currently i only work saturdays, but every time i work there are people coming in asking about that service and how it works.... And theres always different invoices and letters of thanks on jobs well done. If you get a company like that going, then it could be very profitable!
Dman