Can I rip 100 CDs to WAV and come back two days later to batch encode with LAME (through EAC) with tags?

Yes, if you display a little ingenuity. When I rip (with EAC), I get it to put all of the tags that I care about in the filename (so I end up with album - track - artist - title.wav or whatever). Then I use a Python script to encode them all using LAME. Then, when that's done (several hours/days later), I have another Python script which uses a regex to figure out the tags from the filename, and which runs id3tag (from id3lib) to apply the tags.

I'm currently hacking on a Ruby script to generate/tag FLAC files from the WAV files, so that I don't have to re-rip anything in future.