A few years ago there was a similar set up on, I think, a Volvo at one of the plant shows. I was speaking to one of the guys involved in the conversion. What he was saying was as a stand alone conversion it was obviously expensive, but if you were having a machine fitted with a lifting cab anyway the extra was minimal as it was only a slight alteration to the geometry to get the cab to go down slightly below level to reach the ground. Their conversion came down between the tracks so it didn't need to power out as well. That was developed for disabled access, but the extra cost was so little they were hoping to sell it for general use as a health and safety thing not having to climb on the machine for access.
I'm also sure there are grants available to adapt the workplace for disabled employees.