So I was recontacted by a company that does modular aluminum railing. their website is
www.moduasm.com. They have a railing 15x30, which is 15mm thick, and 30mm wide, which has a 30mm wide flat surface on one side, and the modular aluminum slot for attachment on the other.
You could easily use those for heatsinks, then use two pieces of 2020 (20mm) extrusion as frame by holding the heatsinks from the rear or the ends.
If I remember correctly the 1530 heatsink extrusions and the 2020 were around 2-3$ per meter, and there was a tiny fee for cutting to size. The delivery fee would have been a little more then the aluminum, but I guess total wouldn't be much over 5$ per meter, and it would arrive in a few days. Customs would likely also charge something for aluminum, and maybe VAT?
They talk good english though, and they have an email on their site. I'm talking with a few other companies about framing, one is asking about 1.40$ per meter for 2020. If anything comes through with good shipping options I will tell.