Buy.com has the Iogear GKM561R: http://www.buy.com/prod/iogear-2-4ghz-multimedia-keyboard-with-laser-trackball-and-scroll-wheel/q/loc/101/211449589.html
Multimedia Keyboard w/ Laser Trackball for $29.95 + Free Shipping after
rebate.
Get an additional $5 off $30 with Google Checkout, bringing the total down
to $24.95 after rebate.
Tax in CA, MA, NY, TN, WA.
Uses 2.4GHz wireless with 33ft range. Built-in laser trackball with
selectable DPI (400,800,1200). Also has slip resistant design with rubber
grips.