Roku Based Signage - What's the Best Business Model?

I need thoughts on business model for a Roku based signage system I'm working on. I know BrightSign is Roku's high $$ offering for signage but mine will be for the average Joe/Jill shop owner who doesn't have an IT staff or thousand dollars to drop.

Idea is they connect a Roku to a big screen TV, create content online (video flyers for specials, clearances, new products, etc.) and point the TV out their shop window. Idea is that video will draw foot traffic to come in to the store.

So far this a pretty simple and can be done a lot of different ways. The "one more thing" idea with my system is that it is also connected to a video adserver (e.g. Doubleclick for Publishers). This means that the sports store can book ads for gym memberships and sports doctors and run them in her shop (with full metrics, etc. that Doubleclcik provides). The Roku + TV becomes a source of income for the shop owner.

Same idea also applies to churches, waiting rooms, etc.

Question : How to market it as a business - one off license for the Roku channel, monthly subscription, percentage of ad revenue or a mix?

Thanks
Vicky