That's actually one of the reasons I went with a stock H/U. Nobody seems to handle the clock thing correctly. A lot of aftermarket radios don't even show anything when turned off!
Good question. Hope you find something, I really hunted for my old car. (Had to be LED, I *hate* LCDs... look so cheap).
** Edit **
You want readable, get one of these
Now THAT would be funny to mount on your dash.
** Edit again, I'm obviously running through eBay **
would be perfect.