I'm thinking that's what they will do.
My prediction:
Current 8GB iPhone 3G (low-end version) = $99 (entry-level)
New 16GB iPhone 3G Pro = $199
New 32GB iPhone 3G Pro = $299
I remember reading somewhere that inventory is low on 16gb models, and that's why I say they will discontinue the current 16GB with the new one and continue to sell the 8GB for a new low-end price of 99 bucks.
But with recent news (today) of a possible new 'low-end' phone as well as a 'high-end' phone have me speculating that this 2,1 and 3,1 numbers are associated with these two new models. Who knows?