I would think that a few K of RAM to support a flash card is nothing!! Afterall the sector buffers alone take 512 bytes each!!! If you want something lean and low cost you will not get much.

To get any kind of performance with a flash card to support for a file system will take a decent processor. I would think something like a C8051F124 type part would work marvelous. That part has 8K of RAM on board anf 128K of FLASH!!

Scott,
if you are designing a commercial product, the $10.000 for the 'authorized' driver is nothing.
Thus I assume you are an amateur.
I know people that will make $10 worth of meat taste less than delicious because they save $0.10 for a spice.
If you are trying to make something that require a bit of horsepower, it is silly to try to save $10 in a $100 project by using a weaker processor.

Ever so often we see "I want to make my $2 processor sing the national anthem" and the reply is "you need a $10 processor or $25 worth of aspirin". I realize that the budget of an amateur can be very limited, but saving in the wrong place can hurt you more than the savings are worth.

So go buy a F120 development kit, I know that $149 may be a lot of money for an amateur, but you will gain so much from doing so that it will be worth it several times over. You get an ICE equivalent, ability to (re)program seamlessly and a piece of proven hardware to compare your stuff to.

Erik