I would buy the 64gb if offered. Heck, I have a 128gb iPad 4.
Funny story this morning. A customer at a local corporate store asked as well about a 32gb version. The sales person actually told him you can transfer apps to the expandable storage. Jeepers. To avoid the inaccurate information, I politely corrected the salesman and he stated I was wrong. Double jeepers. The misinformed dude also knew better, but I could not keep quiet.
Yes, I was there asking about when a larger size would be offered, but based on the discussion above, not the best source for the answer.