It has been done but unless you can find someone willing to do a swap buying all the parts from toyota seems to be costs prohibiitve. That said I dont recall ever actually seeing a number for all the parts but I do recall seeing someone who did a true Toyota heat seater install (switch, heaters, harness etc) and it was well over $1000 so based on that and the "option" costs of the tray when buying new its going to be far to costly for anyone to do the swap without a donor truck.
There was a group buy not long ago for a 3rd party option that didnt look half bad if you really want a slide out.