Since the VFO in the '101E runs between 8.7 and 9.2 MHz, it would be difficult to find a stock display to cover all ranges from 160-10 meters, but it would be a piece of cake to find one that covers just the VFO range (check http://myworld.ebay.co.uk/jpl995/
for one). You would then have to add or subtract the mixer frequencies and the display frequency to know exactly what frequency you were tuned to.
A different approach would be to use a frequency counter loosely coupled to the output stage, after the filtering, and read the transmitted frequency there. Trouble is, it would only work on transmit.
However, unless it is critical that you know the exact frequency, the '101E's tuning dial and calibration switch should get you an accuracy within 500 Hz or so of the crystal calibrator.