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So you need a 'referral' whois client then. For 100 queries you might just as well use a bulk register request (50 max but do it twice) like Godaddy offers. 100 queries is peanuts. Take care about spam
Godaddy.com > bulk check. If a domain is taken it should give a link to the whois, from where you can get the email address. But take care with UCE. This only from memory - maybe it's changed - try it anyway.