Actually if the domain has been owned for a certain period of time by that person and shows ovt/w history than yes Clickmojo.com is your answer. It is called " domain lead " . A great tool and lead to a deal that would have been one name to multiples, on several occassions. It doesnt always have results as the name needs to meet certain criteria but criteria I would want to see in order to buy the name any ways
Sign up, great service and I think they just dropped fee to $3X a month? Well worth the money!
Heres a simple tip or a poor mans solution.
When you check whois it states " " owns XXX other domains. Copy, paste, google and add keywords to help. Not the best solutuion but I do it daily when Clickmojo has no result or I am researching an owner.