MMC doesn't have chip select so any mod would only be compatible with SD cards.
We'd also need to find an appropriate chip select line. Can this just be a GPIO line? I dunno. We also would need to get an SD card driver in to the kernel (sounds like this has been done).
A nicer option would be to use the second MMC/SD card port on the CPU, but finding this might be problematic. Is support already present in the OMAP1710 kernel for the second MMC port?