Is the "CD Partition" specifically CD Sized? OR can it be DVD sized?

I've been wondering if I could copy an ISO image for a DVD into the partition and boot a machine from the volume?

I'm using a 16GB Sandisk drive that had U3 on it, but when I tried to resize the CD partition to the size I needed, (2.5GB) I got an error message. Because I'm not familiar with low level SCSI programming, digging around in the code didn't make it obvious to me what the error message meant.