Local to FTP folder sync'er, that syncs when any "watched" files change

I have an idea for a desktop application. It's something I've needed for years, but haven't found anywhere. I write a lot of php in my day job, and php web apps need to be developed on a testing server. It's a pain in the ass to make tiny changes to local code and then switch to an ftp app to upload them, then refresh. Same goes for image files. Tweak, save, upload, refresh. If there was a Mac app that would watch (really watch, not just check the mod dates on an interval) a folder and it's sub folders, and whenever a file changed it would upload that to a mirror folder on an ftp server, (and for bonus points, refresh my browser of choice) I know I, and a lot of other web developers would pay good money for it. But I'm not a Mac app programmer. I'm proposing that I design the UX and UI of the app, and you program it, and then we put it on the mac app store and rake in the cash. I'm willing to pay for the initial development, but I'm not a rich man, so I can't afford much. Instead I'm proposing that I pay a small amount- a few hundred dollars, let's negotiate- and we split any future earnings 50:50.