So, this is my idea of using parametrized subckts with spice.
 
	First I create an input file like foo.cir and I include commands for
mslib (*MOD, *SUB, *LIB) in it. Then I run "libprm -n foo.cir". Libprm then
runs mslib first to get all models and subckts form given libraries and then
runs spiceprm to evaluate all used parameters.    
	This works quite right for me, and I hope that You will find my idea
useful. Spiceprm is not my program (I get it from Internet), but I think
that it will better to enclose all used programs in this packet. Spiceprm
has it's own directory with very good readme and examples. If You want to
find out more about libprm or mslib look for the source code. These are rather
short and easy programs - they are all that I could write in quite short
time.