If you are wanting to do this via your own interface you could leveage the APIs or SQL to do the following.
Resource: "Manufacturers"
Add/import an item per Manufacturer, could use Data Connector and pull in any info you wish.
You could then create a Resource of "Model", add/import a list of these.
Then create a Resource Association of Manufacturer to Model and link these however you wish, again this could be done with your Data Connector(s) and Import Rule(s).
Then in your UI you could grab the data either via the APIs or write some SQL that then uses this association(s) to create a casading combo.
You could then set these values against the data class on a computer for instance.