Focus better on a 40D/50D versus the Rebel Series?

I want to assume the focusing would be better, but is the focusing on the xxD series better than the rebels? I was shooting some tennis players the other night. It was dark enough(even with the court lights)so I was shooting at ISO 1600 with a 100mm f/2.0 @ 2.0 and 1/100 sec. while using my tripod as a monopod. The camera/lens just did not want to focus fast enough. I don't plan on upgrading soon because of financials, but I want some combo that can focus better for sports. Any suggestions?

Focus Tracking on my 40D is a lot better than onmy Rebel XT, don't know about newer rebel models though.

The EOS 400D has the same kind of AF sensor as the 30D. I don't know if later models in that series has any improvements in that field.


Butthe 40D is a step up from the 400D.