I have several domains that are targeted for niche keywords. They all rank very well for their keywords, however, the websites themselves are very plain looking. Rather than update each site and risk messing up the sites' rankings, I'd rather redirect all the domains back to my main site in a manner that is not detectable by the search engines.
I'm not looking for a simple "301 redirect" or any other method that will affect my sites rankings. I want these sites to continue to rank but be sneaky redirected to my main site.
In your bid, please detail how you plan on accomplishing this and provide working examples if possible.