ACR camera settings lost with 50D?
Adobe did not officially list the 50D as being supported for 4.6, when you see how it works with the higher ISO settings I'm not surprised.
Hence why the special profiles not ready either.
Also - they're already talking about ACR 5 for use with PS CS4!
As I've noted in a number of other posts, I think it's all about the NR approach that Canon has taken with the 50D.
Having said that LR2.1 and ACR 4.6 is OK for ISO 100 and 200. Like you I hope they get ACR working better with the 50D, LR beats DPP hands down.