Converting an iphone into an ipod touch

Hi guys, I want an ipod touch with a data connection, but it looks like Apple is never going to release that. I don't want to sign up for a phone contract with the iphone, so would it be possible to insert a 3G data SIM card into the iphone and just it for data? Like the ipad?

Essentially that would transform the iphone into an ipod touch with data if it could be done.

By the way, I"m not living in the US and iphones come unlocked in my country.