The DC is running an embedded Windows, which means it's probably running some PC standard ATAPI style interface. So, the likely answer is it can be done. Why, I have no idea.
I know I'm late here, but...
The Dreamcast is NOT running an imbedded Windows.
There is a version of Windows CE that is COMPATIBLE with the Dreamcast, but it is not contained on the hardware, and any software that wishes to use WinCE must include it on the disk(such software is readily identifiable because the licenbsed by Sega splash screen also contains a "powered by Windows CE" logo).
Besides which, WinCE was designed for non-PC applications, and regularly runs on systems with no drives whatsoever.
And it's quite possible to run "real" Windows on a system with no IDE interface, and thuse no ATAPI layer.