I'm glad I did. The SE44 (as with most current Qualcomm-based phones) can play MP3 ringtones, as long as they're 16kHz sample rate, mono, and 24kbps data rate encoded. There's a program out there called bitpim that will talk directly to the filesystem inside the phone. Easy, right?
I fired up Audacity and made up a 45-second MP3, properly encoded, of a dramatic sequence from the original ending theme to TRON. That's where the trouble started: The OS X version of bitpim wouldn't talk to the phone at all. I fired up Virtual PC, installed the Windows version of bitpim, and talked to the phone - once. It took me an hour to discover that I have to completely exit and restart Virtual PC before I could talk to the phone a second time. That done, I downloaded the ringtone, tested it, and went to bed.
This morning, I realized I needed to remake the ringtone: I'd forgotten to cut the volume of each of the two stereo tracks in half before mixing down to mono. I redid that, then made another of a 30-second segment of The Animaniacs Suite with a very nice orchestral rendition of the theme, and downloaded both to the phone.
Now, personal contacts will play the Animaniacs theme, and business contacts will play the TRON theme. Life is good.
I may pick yet another song - probably an Alan Parsons instrumental - to use for unclassified contacts, but that can wait a while.