Me Too! Here's what Pioneer says:
I have been looking at the exact same thing, and called Pioneer's engineering dept. in CA yesterday to aske them what the differences were - the local A/V shops here told me that the models were "vastly different" and weren't compatible.
Turns out "vastly different" means not enough room for markup and huge profits
The actual panel is the same in the pro and consumer grades, the difference is in the connectivity and the bells + whistles. The pro model is a display only, and is configured to accept a computer input, whereas the consumer grade accepts the HT type inputs such as component, s-vid, etc. If you buy the pro model you'll probably need to spend $300 on a card to get the right inputs, but it's still cheaper than the consumer grade.
Also, there is no tuner in the pro grade but with many people using the dist or cable, that's not such an issue - I'm still trying to get an answer on the processing, not sure if 3:2 pulldown is included with the pro model or whether you have to buy an expansion card (about $500 or so) to get this feature.
I plan on going for the pro grade this month.
Jeff