This is still a need huh?
I found out about that need back in the old usenet days. I had a page on one of those free page builder sites, I can't remember now. I used to get all the paper magazines and listed, by month, all of the herp shows across the US. It grew to US, Canada and SOME Aussie shows. I wish I could remember what the site was called, I'd use the wayback machine. Dangit.
Anyway - I ran that for a lot of years.