Why on earth would you want one anyway? It kills the engine

and stinks

and takes up all the luggage space

your insurance goes through the roof because its no longer a standard vehicle and you have the added extra fuel tank in the event of an accident and the servicing costs are far far higher. And then when something goes wrong it'll cost you and arm and a leg to put it right.
Sorry had a LPG Ulyssis, Scorpio and Mondeo and never again will I stray from a beloved diesel (except for a Mondeo that might be petrol) we all learn from our mistrakes.
My poor Scorpio (RIP) had its first replacement engine at 72k, its second at 118k and blew a head gasket on New Years Eve at 131k. In between it had a love affair with the mechanic who it seemed to spend more time with than me.