Keith,
I really like the Kensington products. I have long had a Kensington USB "Studio" mouse that doesn't have the thumb buttons, but it has everything else. Kensington's Mouseworks software (comes in the form of an OS X preference pane) is fantastic for customizing the buttons on an application by application basis.
Kensington make this same mouse in a wireless configuration. It doesn't have a scroll wheel, but rather a touch sensitive strip. To either side are the left and right mouse buttons, plus a smaller third button behind the "scroll pad." The Mouseworks software supports toggling between vertical and horizontal scrolling, custom "contextual" button configuration, and "chording" of the left and right buttons (gives you one extra click). There really is no better software than Mouseworks.
For my Powerbook, I have a Kensington Bluetooth PilotMouse Mini. I had to wait for the latest release of the Mouseworks software for this mouse to be supported (it worked, but I couldn't custom-configure it). I like this mouse because it is nicely textured, it is smaller than a "normal" mouse (portable), yet large enough to hold in the hand comfortably. It has a weight and feel that I really like. It isn't rechargeable, and it would require an additional Bluetooth "dongle" to work with your machine, but it is a very nice peice of equipment. With Bluetooth turned on, I only need to flip the little switch on the bottom of the mouse, then hold down the mouse button for a few seconds. It pairs up via bluetooth, and the Mouseworks software recognizes it and becomes active.
Needless to say, all of this works flawlessly in Tiger, especially with the latest version of Mouseworks. I would recommend that you give the Kensington products a good look before purchasing anything. They are somewhat more difficult to find, but they are worth the hunt.
Scott