Not that I've seen, at least on an Explorer. There really isn't any room in the engine compartment to add something else to the belt drive (other than a supercharger) that is as large and bulky as another A/C compressor.
It may be posssible to add a smaller compressor that has a drive pulley configuration suited to such applications, but there are plenty of better on-board compressor options without having to add another component under the hood.
Generally the A/C compressor to air compressor conversion is just done on a vehicle where the owner no longer wants to pay the maintenance for the A/C system, so the compressor is repurposed for on-board air rather than removed since it's already there anyway, and removal requires a shorter belt.
Other factory on-board air options include the rear side panel mounted air compressor for the adjustable air suspension on the Limited models of the Explorer that had rear air shocks from the factory.
