Has any body ever seen a diecast model of a Ford Sierra XR4i as you would like to purchase one?

Yes, diecast models of the Ford Sierra XR4i do exist, though they may be somewhat rare. Various manufacturers have produced models in different scales, such as 1:18 or 1:43. You can often find them on online marketplaces or specialty model shops, but availability may vary. It's a good idea to check collector forums or websites dedicated to diecast models for specific listings.