A new vendor with a new product is coming to the GA Mt. Eggfest. This is their first eggfest and a sort of "coming out" with this new product. From their web site :
"Our SS Vented Cap is Stainless Steel (304 grade), the same material used by BGE for the lower vent, and like the lower vent it will not rust or break like cast iron."
It's a fully adjustable cap the replaces the DMFT that comes with the BGE and shields from rain, snow, etc.
It looks like a high quality product from here!
Check it out: http://www.eggware.net/