Too late, Steve. Bad things usually happen when I am bored and have time on my hands. But this turned out pretty cool. I basically used 'stuff' I had laying about, and spent a grand total of $6 for a mesh head. I knocked the air vent out of an 8" tom I had doing nothing, and put in a 1/4" jack. I know I coulda/shoulda/woulda used an XLR, but I didn't have one, and I saved time not making the air vent hole a whole bigger. They seem to start out as 3/8" to begin with, which is perfect for a 1/4" jack. I did have the jack with a longer than usual thread, which is what you need.
After taking the original batter head off, I put the 8" rubber-surround woofer on top of the shell, and put the rim back on, with a Pearl mesh head (just for protecting the speaker).
And I wired the speaker up. Simple.
I took a chopped down mic stand that I was using for micing guitar cabinets, and the tom fit quite nicely on top, once I used a memory lock to prop it up. Done. It works tickety-boo. But I am lazy by nature, so I didn't want to waste a day doing this if it was more trouble than it's worth. Oh, and 'instructables' has the greatest non-porn web site
ever . Also gearslutz has a few threads on this idea. Many people say you need a pad because the signal is actually hot enough to clip your preamp. Someone built a pad inside the tom shell, but I use a DI box that already has selectable pads, so this project is done (impedance matching and padding done without any work or extra $$$ involved). And working quite well. I paniced for nothing, and made you give me some answers that I ignored and jumped right into the deep end. I apologize for that.