As per the link I posted before - You can order one online ranging in price from $55 to $140 depending on the capacity by following the below link. The company is in El Paso, TX.US
If I can get a cheap ide hard disk drive for this I can at least know I salvaged this.
Availability is going to be the issue as these type of drives aren't manufactured anymore.
If your looking to find a Brick & Mortar store (ie: building) to go and look for one - you would have to find someplace that deals with used equipment.