It was a market research post, not a product announcement post. While it would be great to see him post that he's following through on it, he probably won't say anything until a product release is imminent (assuming he even decides to follow through). And like swamprat just said, complex products take a long time to go from concept to product availability.
I think it's safe to say that MANY of us would be all over a well done light gun solution for MAME, but expressing disappointment isn't going to get us such a product any sooner.