Lazyweb, please help: I need a sewing machine part

Nekkid, I have a Singer machine, one of the classroom models, and sometime over the last year the bed slide vanished. I have the part number, but I haven't been able to figure out where to actually buy it. The Singer website doesn't actually sell parts, just feet and similar accessories, and it was the same with the other sewing machine sites I found. The only brick 'n mortars that the Singer website recommended for buying parts are several hundred miles away.

Where can I buy a new bed slide?

And how the heck did I lose it in the first place?

UPDATE:

With the help of the lovely ishatirith I was able to find an online store that stocks repair parts. Thanks!