If you could make a version that could be mounted to a shopfront window/glass to hold a big/long cut vinyl graphic to make 1 person installs easier, i could see you selling more.
most sign shops will have a laminator/mounting machine that work the same way essentially. They sell 1400mm wide mounting machines brand new for $800 here, and that's on a stand with wheels, and you can mount up to around 20mm thick substrate. When I had one, I could easily laminate up to 2 or 3 metres length with it (usually 30" media out of my sp300v).
I have been thinking of fabricating some sort of "bridge" type device that holds a graphic up in the middle while you get your act together (hold everything with one hand), then let it go so you can do your thing.
Having said all that... I know some guys who specialise in small format graphics - POS items, countertop displays - and they work in limited space - This device would be suitable for such an operation - and I would say moreso for cut vinyl than prints (I can imagine there being some failed mounts with prints - cut vinyl is more forgiving with these systems).
Best of luck and let us know how you go.