No, I don't think so. An Uno has a 16MHz clock. Logically it would need to be at least 20MHz to produce a 10MHz signal with 50% duty cycle. But I doubt that's possible even with a 20MHz clock. Also it would be a waste of a microcontroller just to produce that signal. Look for a clock generator chip.
What connection does you question have to either LEDs or multiplexing?