I don't think it is. The reason old HiloTrons are as short as they are is because the magnet sits in the space vacated by the missing second coil. With both coils, the magnet has no place to go but underneath, making the pickup taller.Another option would be to find a custom pickup winder to build a filtertron that would fit that route. Not sure if it's possible.
But I don't know much about magnets. Maybe a neodymium magnet could be made thin enough for a Hilo-size Filter but still strong enough to function properly. I suppose a experienced pickup guy would know.