I would venture to say that the location of your site -hosting and contact information in Whois would play a part in localized search results. Which is a key focus of the Search Engines.
I do not have any testing data that suggests Google is actively cross referencing whois as a way of culling out or limiting companies from expanding their web -estate holdings appearances in Google.
I do know for a fact the WHOIS information is used to eliminate sites that insist on making themselves a nusance and have no real value beyond a billboard in cyberspace.
I have seen what a search engine blacklist actually looks like. If you are going to be in Miami this weekend I can show you the criteria and guidelines a specific engine used and the comments in their blacklist database.
Most of the information regarding a site’s history can easily be found using tools like waybackmachine.org and Alexa.com or look at all the information you can grab at sites like faganfinder.com. All Tools I use when looking at affiliate applications and programs I may be interested in.
If you are having a tough time in Google but doing well in Yahoo, take a peek at http://www.doubletrust.net it give you top results in both engines and shows you what is in one but NOT the other.
As for Google, right now they are in update mode. If you are using 302 redirects please change them to 301. You will correct any problems you may be having. You will also want to make sure you have the non www version of your site directed to the www version to consolidate your links inbound and prevent a nasty surprise. See link below for a better explanation.
Using Canonical Domains to Sabotage Competitors in Google
http://www.threadwatch.org/node/2817
Ginette