If you where able to up the memorey yourself, their would only be 2 options, wifi + 3g and just wifi.
The fact that they have listed set memorey configs says to me, once you have bought what you picked, your stuck with it like it or lump it.
Very much doubt youll be able to add any yourself, I mean, they cant even fit a user replaceable battery on it, so I very much doubt a user can add more mem!
Q1: I'd like to buy a 16gb iPad and upgrade it later to 64gb. Is this possible, either through Apple or a third party?
A1: Though Apple - almost certainly not without replacing the entire unit! Through a third party - possibly (if someone is willing to pay, but I don't see why they would - see below).
N1: With the economy the way it is, I'm sure lots of people would like this option.
N1A: Not when you factor the cost of shipping ($40 registered), labor ($100 at least - BGA resolder work is a bit of an art), and new chips ($100). Apple buys chips by the millions - I buy them 100 at a time max. Guess who ends up with a better price? You just spent 1/2 the cost of a new 16GB unit on a memory upgrade - better to adopt early, use, sell, and buy version 2.
Q2: Will it be possible to go beyond 64gb when higher density chips become available?
A2: I'm pretty sure you mean something like, "will higher density chips be compatible for an in-place upgrade?" Sometimes yes, sometimes no. If the higher density chip is released within the same 'family' (e.g. Samsung's moviNAND), they the answer is usually yes. If a 128GB chip is released in an entirely different package and technology, then usually no. You used to be able to piggyback memory chips with some success, but the new chip packages don't lend themselves to that, as they have the chip and memory controller in the same physical unit (not to mention the BGA packages have contacts under the chip).
