Use of multiple sid files

[Lee Keel]

Just wanted to ask the list for some opinions on what the best approach would be:
 
Problem:
I am serving aerial images for areas around larger cities.  I am using Tiger shapes for the area around where I don't have images.  These images are several hundred gig worth of sid files that I am serving through tilecache.  So, once I seed the cache, these files won't be accessed again until I get new sid files.
 
What I am currently doing:
I am currently using a tool that creates a bunch of batch files (http://sourceforge.net/projects/batchsplitter/).  These batch files use gdal_translate and gdaladdo to create individual tiled tif files, then using gdaltindex and shptree I create an index shape file for the tifs.  As you can imagine, this is very costly in space and has grown to have some complications.  Namely that there are holes in my overall shape file but there should be images available.
 
Just curious:
I was wondering if I could do something with tile4ms, but I don't know anything about it and wasn't sure it would be the solution I was looking for.
 
I am open to any suggestions regarding the best way to serve these images.
 
Thanks,
Lee Keel