Looks like you would be interested in doing something unique and not leaning towards a franchise. Do you have any experience working in the fast food business ? I think that is a very important factor.
A couple of things is what I would do if I were you..
There is a lot of information on the web ( costs free ). I would extensively research on what it takes to start something like that,
Key points to look for,
Cost / benefit analysis
Suppliers for restaurants ie. Groceries in bulk etc..
Success stories etc
In a week you could put together a lot of that information on paper and get your business plan going..
The second step to this and perhaps the most important and difficult part is figuring out the Location.
Who would be your target audience Offices during lunch time or more laid back place, the affluent crowd or the blue collared folks etc etc..
Based on that, I would look for an area where we could possibly sell enough. I would even go to the existing businesses and sit there and observe the type of crowd coming in during extremely busy hour and also at the slowest times.. See how many people come in and what kinds of cars do they come in.. All that needs to be factored when you price it..
And then do you want to do a high volume-low price or low volume-high price?
Search for businesses for sale and you should find plenty of websites that cater this..