Cacheing Tiles for WMS

[David Bitner]

I use a number of WMS services for displaying imagery both for local
client applications and for inclusion in Mapserver.  A lot of times
these services are slow or require an additional step of projecting
that slows them down a lot.

The idea I have is to create an application that sits in front of
Mapserver (working as a WMS) and takes a request for a map and
automatically splits the request into tiles that fit a shapefile with
tiles for different scale ranges.  Once the tiles are there, it would
then call mapserver on the shapefile index to generate the image to go
back to the client.  It would basically act much in the same way as
Ka-Map only completely on the server side.

Has anyone ever done anything like this?  Does what I am proposing
make any sense?

Any ideas on different ways to implement something like this?