Client as Art Rep?

[Jen Reinstadler]

I have a client who is more than thrilled with the portraits I've done for him. He is an artist of sorts himself, making and marketing custom knives and carved gun stocks. He says he wants to take one of the paintings he commissioned from me on the road with him as a backdrop or decoration for his booth. He's also very social, and he and his wife entertain guests about every week. He's sure that he'll be referring new clients to me, and jokingly (though not joking) commented that I ought to pay him a 10% commission for each referral.

My chest tightened when he suggested it. I don't know if it's because of some breach of protocol or something more personal. My husband doesn't like this guy at all, for reasons I won't get into too deeply. Let's just say he's eager, he's persistent, and he's dying to make a good deal.

Is his offer reasonable, or is this crossing a line?