I've ordered an "RSMMC" card from MemoryTen to use as a boot loader for my raspi.  It's 128megs and a slightly different format than the memory that is usually used on raspberry pi - so there is some experimentation to do to see if this will work to boot my pi. It was 5 bucks, so not a huge loss if it doesn't turn out to work.

 

All I intend to store on it is the /boot partition, with a cmdline.txt that points to my actual root drive.  In my case, my pi uses a USB HD as the primary drive so my cmdline.txt looks like :

dwc_otg.lpm_enable=0 console=ttyAMA0,115200 kgdboc=ttyAMA0,115200 console=tty1 r
oot=/dev/sda3 rootfstype=ext4 elevator=deadline rootwait

The important to notice change here is "root=/dev/sda3" - or the third partition on my USB Hard drive.  I have reserved a boot partition and I use /dev/sda2 as swap.

With this configuration, the only thing my raspi uses the SD card for is load the bootcode and kernel, and then mounts my USB HD as the root drive.