I've found 7-segment LED displays are still quite visible down to 0.1mA. I looked at the datasheet for the AT89S8253, and although it can't drive as much as an AVR, it can do 15mA/pin. It's got lots of pins, so you could cycle through all 7 * 12 = 84 segments. With a 5V supply and red LEDs with ~1.8 Vf, 220 Ohm resistors on the common segment would limit the current to 14.5mA. With a 1:84 duty cycle, the average current would be 0.17mA per segment.