The key blank is the same as my 99 Impreza. Don't know if that helps any. Probably means the ignition switch is that same as other Subaru from a similar vintage.
The switch only? Or the whole lock assembly? The switch is available on its own if the key mechanism is still okay. If you need an entire lock assembly with keys, your best bet is to find a used set. They crop up on the Japanese auctions fairly frequently, but they are also available new if you want to buy a brand new set. This link is for a full set for a 91-98 truck, and includes matching locks for the doors and fuel flap. It also includes the electrical switch too: https://www.japanparts.com/parts/detail/?id=64215
