This is something I've been toying with ever since I saw eVGA's step-up program. Wouldn't it be nice if more component manufacturers offered step-up programs?
Wouldn't it be cool to be able to pay the difference between a 4gb kit of DDRII-800 and end up with a 4gb kit of DDRII-1600? You could even have a lot of restrictions on the upgrade option like requiring the memory to be traded in be in perfect working order, require the orig reciept and so on and so forth and people would still hail G.Skill for offering this option even if few actually used it.
I know it wasn't long after I recently bought this kit of DDRII-800 that G.Skill came out with that sexy ass Pi DDRII-1100 and I sooo wanted to upgrade to that ram but didn't want to hastle with selling my ram at a sizeable loss then having to fork out extra cash to make the upgrade while my rig sits without memory ( which in my case I have a 2gb kit of craptacular Corsair Dominator to tide me over but thats me, many don't have spare ram ).
I would still love to be able to trade my ram up for some of that Pi DDRII-1100 but I just don't feel like taking a $10 - $15 loss on my relatively recently purchased ram just to make the relatively small upgrade although DDRII-834 @ 4-4-4-12 with 1.8 - 1.9v is very tempting and is my main reasin for wanting the Pi, that and I like the blue heat spreaders