redline, which was mentioned already, has a 60 day full demo.
you can check the 'new product' section here or do a search on the kvr forums for various methods people are using to add either character or extra 'whatever' to their tracks
there are other options other than preamp emulations for what you want, but checking out redline can't hurt as well as some free stuff from bootsie and jb's ferox (tape emu)