My latest project is called SDD 99 and is both a multi-function expansion card and a PEB replacement. It's currently in the prototype stage and about 80% complete.
The SDD 99 features an SD-card based disk, 32 or 64 MB of SAMS-compatible RAM, Wifi and a remote file server, and various ports. This video shows how to use the SDD 99, but be warned, I suck at YouTube.
The SDD 99 uses an ARM Cortex M microcontroller and one SDR SDRAM IC. Programming the Cortex M has been both