Is it possible to purchase hardware to add Memory to a motherboard?

"No.

There is no way to do that period.

If you have vista this might give you some performance gains using a USB memory stick:

http://en.wikipediadotorg/wiki/ReadyBoost"

"I would imagine that even if it existed in the form you are looking for it'd have a hard time beating the piece of hardware called 'motherboard replacement' for price.

Replacing the motherboard also has the benefit that there aren't going to be any unexpected performance downsides to using a non-standard connection between the processor and whatever memory you manage to add."