I know your intention isn't to fool the search engines, but thats what trying to get a different url to show up for your site, or getting one site ranked that forwards visitors to another site would be essentially be doing.
There may be sites ranked at the top that all have the keyword in the domain, but chances are its their backlinks that got them to the top, not their domain name... in Google especially. MSN probably places the most value in domain keywords, but even they "seemed" to have devalued this sometime last year. At least thats what I saw happen to my keyword domains that were ranked without backlinks.
From May 2008: http://www.searchenginejournal.com/google-yahoo-microsoft-seo-influence-of-keywords-in-domain-names/6955/
Best practices when moving your site - Google Webmaster Blog
http://googlewebmastercentral.blogspot.com/2008/04/best-practices-when-moving-your-site.html