Need a recommendation for a Domain buying negotiator

The best domain for my niche and related is owned by a guy in San Fransisco, and I want to buy the domain from him but I don't want to deal with him directly (even though he has contacted me in the past).

I need to find an intermediary company that can handle the negotiation for me. I don't expect to have to pay much since the guy has been squatting on it for more than 15 years and according to the Internet Wayback Machine it has never actually been used for anything at all - he has never added any value to it. It kind of irritates me that such a good domain has been sitting in this guy's closet gather dust for 15 years.

I know that GoDaddy has a domian buying negotiating service (and the domain is registered through them, which may make it easier), but I really, really do not want to do business with GoDaddy if I don't have too. Do any of you know of other firms that deal with this sort of thing?