It would seem that (in theory) it should be possible to replace the Carbon's Microdrive CF card with a solid-state flash memory CF card. Unfortunately the 2GB & 4 GB flash cards are now about $280 and $570 respectively. While expensive, this would give you a high capacity flash based player. The Micro-Drives are significantly less expensive than comparable flash memory devices per GB, but have lower I/O speeds (not so important with an mp3 player) and are prone to mechanical failure in higher vibration environments.

-Zeke