Most people will want to cash in their investments at some point. In order to facilitate that we'd need a secondary market in these instruments so people could sell them on. The price would then vary based on future earnings projections. Either that or the understanding is that the payments continue until some fixed point in time, or until the investors death. So, depending on how you look at it, these are either dividend paying shares, corporate bonds or a kind of annuity. All of which exist already.

EDIT: although I'm not sure if anyone's really doing corporate bonds that are linked to profits, that might be new.

Having said all that, I agree with Seth that society could do with being a lot more creative in how it funds businesses.