This is a file cache lib that I wrote in my spare time while working on "Hellboy II" at Double Negative in 2007. It was never used on the movie (but I think the Batman "The Dark Knight" team used it). Anyway, it was OSS from the beginning, but I never found the time to upload it anywhere. :)
Finally I got to it: http://code.google.com/p/jupiterfilecache/
I still need to add CMakeLists for it - currently there's just a GNU Makefile tested on Linux.
If you integrate it directly into Aqsis, I suggest you use the same API as 3Delight (http://www.3delight.com/en/uploads/docs/3delight/3delight_50.html#SEC193 - I.e. no need for a new shadeop or changing shaders even).