I have recently completed another project, which is a low-cost Flash HuCard for the Turbografx-16 and PC-Engine systems.
This provides a way for developers and players of homebrew games (& fan translations) to play on a real system. Also, it provides a way to "try before you buy" with commercial games.
Here is the web page that I've made, if anyone wants to check it out:
http://www.gamingenterprisesinc.com/Flash_HuCard/
This is not meant to compete with the more expensive multicarts, that allow you to load every rom ever made, at once. It is just meant to load & play a single game.
It is also very low power, due to the small number of ICs, which would be beneficial for those with battery-operated handheld systems.
I have sold a majority of the initial batch, but I am considering making a second batch if there is interest.
There are also a couple topics at pcenginefx.com (Turbo/PCE Game/Tool Development forum), if anyone's interested.