Bruce, if the 408 does not have motors in it, don't despair: it is not at all difficult to install a couple of motors and wire up the headlights. Just figure that into your price. Lionel motors for the 408 need a "hanger bracket" in the top of the motor frame, which makes them just a little bit different from the usual B-A-L motor. Vintage ones can be found, or you should be able to buy new ones from MTH parts for about $200 each.
RideTheRails: Like so many things in the tinplate world, if you are interested in the Williams Standard Gauge motor unit, you just have to keep your eyes open, know what you're looking for, and pounce when one shows up. I have bought them off eBay and off tables at train shows. They are often mislabelled, the owner has no idea what it is.
Here is the page from the Greenberg book on Williams trains, so you know what to look for (click to enlarge):
The Williams unit is the only one that looks like this. The MTH ProtoDrive is only a single can motor.
The book was written in 1987 and is out of date: this motor unit is no longer made and is not sold by MTH.
Note that the motors are DC, so the center rail rollers need to be connected to a bridge rectifier. The units initially came with the rectifier wired in (that's it hanging between the two motors), but sometimes along the way they have been removed. Be sure the one you buy is complete: I bought one that is useless, as the gears on the axles had been removed and I have not been able to find anything to match.
As is, the Williams motor has no reverse capability. As I said, I use a Williams reversing board (available from train dealers like Train World). This gives smooth, dependable forward-neutral-reverse-neutral sequencing. Since the Williams reversing board has a bridge rectifier built into it, you would remove the one that comes with the motor.
david