Heres a few I found but none of them I really Like to be honest..

http://dev.portalzine.de/index?/Horizontal_Accordion–print

This is a nice effect but it doesn’t seem to work locally, it really does look like the xbox 360 menu bar but it wasn’t the effect I was going for..

http://www.nyokiglitter.com/tutorials/horizontal.html

This menu is not as smooth as I would like and I don’t like the fact the text overflows for a couple of seconds in mid transision

http://www.arbyte.net/f4/

this seems the one I am leaning to at the moment but I’m going to need to look at the code a bit more..

Whilst we are on the subject most of these scripts use moo.fx or prototype… I’ve found these communities ( mainly the prototype community )… elitist and unhelpful.. whilst visiting the IRC room recently I was kicked out because I asked about an accordion script I was developing, the reason was that they had too many queries on accordion and were sick of them, surely if your getting too many queries about a bit of your code, you might need to… work on it or at least work on the explanation and documentation instead of ignoring people’s questions..

And please don’t get me wrong the examples above are good examples of an accordion and the developers did a good job, I’m just astounded at the lack of examples compared to every other menu/navigation type javascript ever made..