I want to approach a former colleague to be a strategic partner on a software project. He would be bringing key skills to the table that I frankly can't afford to pay an employee for. I was considering offering him equity but after reading Joel Spolsky's excellent answer on partners and equity I've decided against it because he is not a founder or working full-time on the project and therefore not worthy of an equal stake. And, I'm sure with a minority stake he will eventually become "dead weight" (Joel's words).
Since I cannot pay him salary, what are my performance-based alternatives to equity? Any suggestions on what to offer him? BTW he is an executive at a very large technology company, if that is important.
Thanks in advance...