I'm not aware of a Virtual Treadle Kit for less than $5,000, but you can change the treadle plate out to pressure pads with very little retrofit or cost. Remove the inside rollers of the treadle plate. Strip the treadle down to just the flat metal bottom plate. Replace the two proximity sensors with pressure pads. Leave the reflector strip in place. It doesn't create the nice clean floor of a virtual treadle, but makes it much easier for older drivers to get into place and at a fraction of the cost.
That said, because the drivers side is no longer a set point and this fix will not provide sizing for that side of the car, you may loose some cleaning capability. The loss of cleaning should only be slight though.