Can the entire MTD be used as RAM?

As you can probably guess from my question, I'm a newbie to embedded Linux. Be it as that may, I see all over the web of how people keep trying to use the MTD as a replacement to block devices like IDE hard drives. Well here's my big question:

Could the embedded Linux device be handled like so:

1) The contents of the MTD be backed-up to a PC hard drive.
2) The bios rewritten to see the MTD as RAM (slave?).
3) The device (such as a non-smartphone) uses a true block device (SD card, M2 card, etc.).
4) Xorg reconfigured for the esp. small screen and cursor control.
5) A modded version of Puppy or DSL Linux be loaded onto the partitioned memory card.
6) A partition on the memory card (block device) hold the contents that was originally in the MTD, so that Qemu can reach said partition.

Course I don't have any idea about the CPU's that the typical cell phones uses. Like for instance my Sony Ericsson W580i? Are cell phones so different from each other, or do they have the same basic components (however how proprietary)?