using grass to make high quality maps

My question probably has more to do with computer graphics and output than
with grass in particular. I'm interested in making large maps of a
professional quality -- and in using GIS-style routines like contour
shading, slope and aspect stuff, oblique viewing angles and the like -- the
kind of stuff I know many GIS's are capable of -- and am assuming grass is
also capable of (isn't it?), but my knowledge is weak at a more practical
level. Seeing as I don't have high quality plotters at my disposal, how
would someone like me go about the printing part of all this? Are there
printing companies that can accept a standard sort of data file or files
and produce large, high quality (and hopefully color) maps? I know many
printing shops can accept Macintosh data from programs like Adobe
Illustrator and especially things like Quark Express. Would I have to
transfer the map from grass into a package like this, and then go to the
printer? Are other people doing things like this? Any pointers?

Thanks

Paul Fly