Came across the following ...

http://blogs.zdnet.com/Google/?p=502

Might it be implied that from the 1 April 2007 Gmail might leave beta and go 'unlimited'?

Of course :)

Also the fact that the link to Google News has been replaced by a link to Google Reader* when Gmail's inbox is empty could lead to other speculations.

Note: It will never go unlimited. Remember that some people pay $50/year for 10GB + other features? Remember that Sergey Brin said they'll give extra storage as a paid option?

* "No new mail! Want to read updates from your favorite sites? Try Google Reader."