Well may be i don't understand right enough you question, but i'll try to answer it
If you want to do some kind of domain look up, you can try this trick:
- copy a search query from a search engine like alltheweb, google, altavista, (or your favorite one) made with a domain you know it exists and with a fake domain.
- Use this string in your site and replace the domain name with a variable
- Use some forms in the page with the same variable as the last step
- make a some rule analysis to check the result page and translate it into your site
- Voila it is ready
May be sound a little bit hard to do, but if you are ussing perl or php it is not hard.
Of course, you can use the results of internic too.
And if you do not trust in one search engine or internic, you can make more than one search and contrast all.
Hope it helps...