I will try to answer all questions in one post.
Comments: each flavor is actually a blog post and has comments enabled. You have to be signed in to comment but it accepts openID, google, aol and other logins so you do not need to register to comment or vote.
Adding juices: unfortunately unless I get someone who wants to help add them, I am the only one who can do it for now. Since each flavor is a new post I have to create them one by one. Please let me know which vendors/flavors you want the most so I can get the most popular ones on first and then I will slowly add the less popular ones after.
Site coloring: I seem to have a hard time with light colored themes and this was the first simple theme I was able to get working with my image of how the site should work. I might add a white one for users to use but I have added a couple hundred lines of custom code to this theme and will have to copy all of that over to the new one. Also, I know the header looks like crap but I suck with graphics and that was the best I could do.
Visitors adding juices: I am working on a way for visitors (non authors) to submit requests for which vendor/flavor they want so i can add those first but it seems I will have to custom code that. I need to learn how to write wordpress plugins so it will not be hardcoded into my install (and break when I upgrade stuff).
Again, thanks everyone for voting for the ones you did. It helped a lot and will give visitors a better overview of the site and make them more liable to rate juices now.