Yeah the Classic control in a sense is wireless, but you need to plug it into your Wiimote on the bottom where the Nunchuck would go.
As for Wireless Gamecube controllers, there is one..the Wavebird Wireless Controller. You can't get those in stores anymore as a rule, you may be able to find one or two in some stores but for the most part you may need to go to online sites to buy a Wavebird.