hellonearthisman: I recently Installed BerryBoot http://www.berryterminal.com/doku.php/berryboot
It downloaded and installed Openelec v3 and Linux (minecraft) too. Dual booting on a 4GB SD card, no worries.

To get more speed, some people say using a fast USB key, installing the os...

I found using a good USB stick (I have quite a few and speed tested them all to find which one was best) with a slower SD card did help as did getting a class 10 SD card.

It's relatively easy to transfer the main OS partition to a USB stick and tweak the boot settings.