I guess not a whole lot of interest at the moment, but just some of my thoughts from the last couple days.
First off, a booze pass can be done as a stand alone pass with or without cigars. For the samples, boston rounds in either 2 or 4 oz sizes could be used. They are inexpensive at only about $1 a piece through amazon.com as well as a few other websites. For the shipping I was thinking of using foam blocks or sheets cut to the size of the shipping box. Spaces could then be carved out in the shape of the sample bottles.
As for the format of the pass, I think that separating them by spirit type might be the best route. For my purposes, I was thinking a whiskey pass with several different sections would work. Section 1 could be Bourbon, 2 could be Rye, 3 could be scotch, and the 4th could be marked as other(corn, wheat, malt, Irish, Canadian, etc.). Other ideas could also work such as a scotch only pass with each section representing a different region of Scotland. An all inclusive pass that has a different section for each spirit type(whiskey, rum, brandy, tequila) could also work. A pass could have 4-5 sections with 10-12 samples per section giving a decent selection of spirits.
As pointed out by Jake, figuring out a fair trade system would be a bit difficult given some of the rare or hard to find spirits, but I would think setting some ground rules could be worked out along with communicating all P/T as they occur.
I would think that adding a sampler to a cigar pass would also work well. Say a 10 bottle sampler that everyone did a trade with along with the regular cigar trades.
Any other thoughts are welcome.