But this is what the filter tab and the query section in it are for. Create a query for all of your gifts with the subtype you want and link it to the filters tab. They just can't put everything in - and that is why they gave you the query option.

I'll second what Melissa posted. In this case, all you need to do is create a query based on the gift subtype, then move over to Export and drop that query into the "selected records" criteria on the main export set up page. I don't see the purpose of your suggestion b/c you can already accomplish this task quite easily.

Lisette's suggesiton works for gift exports - mine works for constituent exports - but pretty much all around this is possible with the current software.