Here's the thing, I just succumbed to temptation and bought an A900.
I go off for a short break (I know, I know, yet another) in the Moselle valley in a couple of weeks so what to do about flash memory?
I have two 8GB Sandisk Extreme IV (45MB/sec) cards and an older 4MB Ultra II (15 MB/sec).
On the A700 that's a 1000 RAW images but only 500 with the A900.
16GB Sandisks run out at over 100 apiece from a reputable supplier, granted they are 60MB/sec devices but I don't need that.

The solution, a 160, "Nexto" 320GB portable backup device.
Basically it's a Battery powered, 320GB, 2" SATA hard drive and in size is, unsurprisingly, similar to a standard 2" ext. drive but about twice as thick.

The NexTo LiPol battery does 60GB between recharges and if thats not enough (it is for me) you can buy an external battery which is good for another 80GB. Charging is done via USB or a provided mains PSU.

Attachment 54097
It connects to the computer through either SATA (best 60MB/sec) or USB cables.
It takes CF cards or a whole bunch of Memory stick/SD variants via a second 4in1 slot or via USB.
The device contains a microprocessor and eeprom software which allows for several functions but I'm only concerned with one (for now).
That is, automatic transfer of images from the CF card with data verification.
This function is selectable via a simple Menu System on the front LCD.
Attachment 54096
In use, nothing could be more simple, plug in the CF card and the NexTo recognises the card, creates a new folder, copyies all the images from the CF card, compares the copies with the originals (veryfying) and then deletes the CF card ready for it to go back in camera. The whole process takes less than six minutes for my 8GB Sandisk. A different folder name is generated every time you put in a CF (or other) card.

When you get home just plug the NexTo in with the provided SATA cable (or USB cable) and shift them to your hard drive. Here's a screen shot of Windows File Manager showing the NexTo plugged into the computer and showing two 8GB transfers from CF.
Attachment 54098

Nexto link