I agree,
I wouldn't want 50000+ individual meta titles either. I would like to see just one "custom search text" just for locations. Just like you can choose to use "custom search text" for all search results.
For example at the moment I use "custom search text" to show my site name at the end of listings. I would like to use a seperate "custom search text" just for locations. So that if I was viewing a location, say london, the title could be : "London Free Classified Ads", the "Free Classified Ads" would only show when viewing locations.