I'm up well over a thousand billion passwords now--I've not looked at the system for an hour or so now, so I'll leave the system running until 10-11PM tonight.
As for decoded plaintext, a whole file is the best. I'll try injecting an unencrypted file into the mix and see if that has any results (I highly doubt it will). So far I've been brute-forcing using Zip Key from Passware--using all capitalized and lower-case letters, numbers, symbols, and spaces. I should be up to 8 characters now--the max that Passware would let me run. I did a 1-8 character attack. On the same computer I'm doing a Xieve attack which is going up to 14 characters.
Try to get into contact with the creator--any lead we can get on the length will be appreciated--meaning number of characters, type of characters, and possibly a copy of a file. I realize that it being made in 2001 is a daunting task...