It wouldn't be too difficult to make a turn signal switch out of parts from radio shack.
You'd need a flasher (of the appropriate voltage) to make it work, though. Pretty small potatoes, though.
Personally, I just left the lever there that someone put on there back in the day. It doesn't look too bad, and it's not chrome.
Although, you could just stick your arm out of the window and signal that way...
