Find Domains by Registrant

[irongloves]

Hello,

Do you know if there's a way to find the domain names registered by somebody?

I've used DomainTools service but it's kind expensive (US$2/US$3 per domain).

It's ok when somebody has 70 domains but when you come to registrants with 10,000 domains is kind of overpriced.

Any suggestion? (even paid service is ok for me)

Thanks
Irongloves