No, actually, but thanks.
I have several "small" partitions, one for each version of the operating system I'm testing, and then one big partition for my data. And the external drive.
But iDVD seemingly wanted more room than would have been available had I wiped the start-up partition clean, so my choices were to install Mac OS X on the big partition or the external, so I chose the latter.
Thanks again, tho.