It wasn't easy to make out what you were trying to say. However, I've been searching for the same thing for (more or less) 2 years now, and I think I've found the solution. The alternatives I once considered were the Morpheus Droptune and the Behringer US600. Still I never got to buy either of them because the Morpheus was a bit too big for my needs (and also had a bit of latency and some chords didn't sound right once you started using 9ths, 11ths, etc) and I felt the US600 was the right size, but just wasn't good enough.
However, I found out about the Digitech Drop about a month ago, and after seeing many reviews I finally ordered one, which should be here next week. I for one am not a fan of Digitech effects as I find them to be too sterile compared to other brands, but I do think the one thing where they excell and are better than any other brand is pitch shifting. The tracking, the quality, the immediacy. I'll just stop blabbering and let you look at a few videos on youtube. Go to a store and try it if you can, you won't be disappointed.