I would definitely go that route. Given that apple marks up upgrades 100-500% I would bet the 64GB SSDs will be available for $500-$700 easy.
I would personally also settle for a 32GB SSD, as I do not need much storage.
I am wondering if this will void out any warranty, however. I plan to buy mine at a Best Buy with the 2 year accidental damage coverage warranty just in case I drop it, crack it, or spill something on it. I would hate for an $1800 investment to go to waste.