Is there a way to create a device locator search based on an IFAlias name on one of it's ports?
No, but your interface name will have the device name as a prefix, so if you search for it, you can get the name of the device it’s on. I would be VERY careful when trying to search for external ifalias. That’s a super “expensive” search. You’d be better of using the X_ifalias attribute.
Some further info is available in this techdoc regarding x_Ifalias
CA Spectrum's Internal_If_Alias attribute does not match the devices actual ifAlias entry for ports