Lots of threads on the 3GS obviously, but I've been very careful with my updates on my 3G. I currently have 04.26.08 baseband and unlocked using Ultrasnow on 3.1.3. I plan on upgrading to the iPhone 4 and selling my 3G on eBay, but would like the option to upgrade to 4.0 if the buyer wants. Anything out yet that will do this?