Hi.

Actually, to automatically detect 16:9 anamorphic sources (on the displaying part, not on the DVD player), you should only need to check the voltage on one of the SCART pins. There is one pin (I don't remember which one though), that is set to 6V by the player (if it (and the DVD) follows the specs). For non-anamorphic and 4:3 sources, this is set to either 0V or 12V (I don't remember specifics about this either) . I could try and find out about this again though.
My (rather cheap, 4:3 and non-HDTV) Telefunken TV set is fully capable to automatically switch between 4:3/non-anamorphic 16:9 and anamorphic 16:9. I am not sure wether it differentiates between 4:3 and non-anamorphic 16:9 though, it wouldn't show them any different anyway.

cu,
sven