Well then I can't really help you.
One thing I would recommend is maybe CIB by kalan_vod, or translating all the values from the matrix into a string. That would drastically decrease the size.
I could probably whip up a program that converts a matrix into a string, and converts a string into a matrix.
Although if you did not have decimals in your matrix, I could probably set you up with a better compression rate. Oh, well I will experiment more with it tonight.