You could get a linux mouse. They have 16 buttons, and two scroll wheels all which are configurable and/or removable and five different interchangeable lenses - plus they are skin-able. They are not compatible with many games though.
Also, there is the FreeBSD mouse. It has almost as many buttons and lenses as the linux mouse, but you have to put the buttons and lenses on yourself.
Or consider the OpenBSD mouse. It only comes with two buttons, but it comes with a lifetime warrantee against damage. It has the ability to hold two buttons and a standard lens, but they are not included. Fortunately it comes with a very detailed 78 page manual that explains how to build and install your own.
Lastly there is the NetBSD mouse. While it lacks all of the features of the FreeBSD and linux mice, it has more features than the OpenBSD mouse and is easier to put together. As an added bonus, the NetBSD mouse can operate your VCR, your toilet and your can opener, and of course, your toaster.