I need a fresh N900 to do a few experiments on, but I'm unwilling to let go of my existing Maemo install, which I customized extensively before I discontinued its use and would never be able to restore to current status again from memory. Why? Nostalgia, I suppose, as well as keeping some old apps that I can't find in the repos anymore, or maybe I sideloaded them - who can remember.

Ideally I'd like to do a full clone from USB and store the result as a massive compressed image file, which I could then reflash again to the N900 in case of need, replacing the existing eMMC content.

Is this feasible? If not, is there some procedure approaching this?

Edit: I'm reading up while I wait for answers and I may have explained this incorrectly. By "eMMC" I meant "entire content of the flash drive in the phone".