your TV upconverts? So your saying your TV takes a 480i from a DVD player and converts it to 1080i.
My HDTV upconverts a 480i DVD signal to 720p. Most non-CRT HDTVs do. A microdisplay has a native resolution, generally 720p or 1080p (or 768p, etc) and all inputs are converted to that display resolution. Would an offboard device do a better job? Quite often, yes. But the HDTV itself will usually do the job.
Plasmas, LCDs, LCoS and DLP units display in progressive mode. They'll accept interlaced and convert and scale as needed. Different models and different brands do the job to varying degrees of success. Some accept 1080p as well as 1080i.
