Scott,
The keys on the DGX305 and DGX505 are not even like those of the SD1 or PA1XPRO. These two keyboards actually have metal weights under the keys. I think the DGX series are only shaped like piano keys and are closed in the front like piano keys rather than those narrow synth type keys of the PSR3000 variety. Clavinova keys are what I would call hammer weighted keys.....the feel of a more heavy weighted piano.
I sell the Casio Previa keyboards with a very good Clavinova type action and these only weigh 27 lbs. and the prices are very low. I am hoping Yamaha might be able to develop a keyboard to use in a new model with PSR3000 features, keeping the weight and price down. Even if not, having the 88 DGX505 keyboard would still be great in my opinion.
George Kaye
Kaye's Music Scene
Reseda, California