Hi Brian,
The difference between the Fulvia and Integrale is that the Integrale was produced on the standard Delta platform, which as that was designed for both RHD and LHD markets had the required pressings and apertures on the floorpan/bulkhead for both LH & RH drive versions, which made the job of conversion a little easier. This was not true however of the Ypsilon, which used a modified Punto platform that was never intended for RHD, so again the required pressings, mounting points and apertures were missing - which is why no Ypsilons were converted to RHD even though with the centre console design it would have appeared on the face of it an easier conversion.
Chris