One of our readers let us know that they recently launched a site that tracks Alexa Rank History.
The site call Site Rank History
Alexa maintains rank history for sites with rank lower than 100,000 only and you have to submit your site to the new service to track it and it appears you can only track the sites you own and submit to the service for.
Anyone its free and appears to work.
We signed up for TheDomains.com and MostWantedDomains.com and we will let you know how it works.