The A730 only has bluetooth, but the new A730W has wi-fi built-in and 128 MB of RAM, not 64MB. Bit hard to find the specs, the asus usa website has the details or http://www.mobiletechreview.com/ASUS_A730W.htm for a review.
As for the HDD, something like a compactdrive or X-drive has it's own battery power is what I'd be looking for (https://www.jaldigital.com.au//catal...t.php?cPath=27).
They cost about the same for 60GB as a 4GB microdrive (which are also more of a battery hog than CF/SD cards - and I hope self powered HDDs!). Of course they are a lot bigger, but I just think I'll be using them to transfer memory cards from our cameras whilst on holiday and each night or so move a movie or two onto a SD/CF card for the next day. You can get Divx movies that fit onto a CD ie 700 MB, so at slightly lower resolution for the smaller screens, I'd guess about 2-3 on a 1GB card.