Making a hyper niche app targeted for a large company

So I am a developer, and I had this idea about making an app only for florists. Obviously theres not a lot of money in that so what if in addition to any florists that signed on, 1800flowers or some other large flower company would license it to each of their stores. This would have to be a darn good app for them to use it, but is something like this feasible? And how would I go about getting large companies to sign on the something like this?

Thanks!

One of our clients have a fantastic idea about solving the quality measurement in big companies purchase process (what ever that means). How he got traction from big companies? He was organizing seminars about that problem and explaining to the people how to solve it.

Funny thing is he got 3 preorders from a fricking huge companies (10K employees) and all he has is a wire frame :)

I can't say that I have any experience on getting companies to sign on, but I have got som app experience.

This would be a fairly simple app, yes it would have a lot of data, but the app it's self would be straight forward. Just need to have a large database stating all of the information, which you might find would not be that hard as I am sure there are some databases out there already which you could adapt/merge.