I want to use some combination off Firefox add-ons or other
modifications to give Firefox the functionality that iRider
(www.iRider.com) has as iRider is simply built on top of IE and I'd
prefer not to use IE.  An overview of iRider's features can be found
at http://www.irider.com/irider/index.htm#QuickOverview.  Also there
is a free trial available for download so you can see what I'm talking
about.

Specifically I want:
-a vertical tab bar that opens ALL links in a new tab (including
entering a link in the address bar)
-left click takes you to the new tab, while right click opens the new
tab in the background
-"pinned" tabs that can't be closed (unless unpinned) and remain across sessions
-the ability to size the vertical tab bar (make it wider or narrower)
-the ability to open multiple new tabs by selecting multiple links and
right-clicking (see the section on "Open several links at once"
iRider's quick overview)
-hierarchical tabs
-tabs seperated by website/domain
-the top tab is always your homepage
-the ability to close multiple tabs simultaneously (in iRider you can
do this by clicking and holding the close tab "X" on one tab and
dragging up or down across other tabs)
-the ability to close all tabs, or all tabs from the current site
-zoom in/out buttons (as I my monitor has high resolution which make
some text appear very small)

I don't need, but wouldn't mind:
-"thumbnail" previews
-double clicking on tab reloads its page

Additionally I'd like to be able to re-arrange tabs (not currently
available in iRider)

If you play around with iRider for a short while you'll understand these features.

Thank you.

Your question probably should be posted on 

http://forums.mozillazine.org/index.php?c=4

good luck