A few notes: RAW converters will make bigger differences to the final result than the imaging chips of these cameras themselves. The Sony converter is known as dreadful and does nothing else than the built in converter of the camera. Apple's Aperture is much, much better and will give you at least two stops of advantage with the Alpha 900. Also see this link:

http://luminous-landscape.com/forum/index.php?showtopic=30298&st=0&p=244...

Any settings, like colour space or DRO in-camera do not have any effect on the RAW data, except for the exif. From my own experience it is much better to convert RAW (any brand) into a bigger color space than the rather limited Adobe RGB 98. Crippling the colour data first and then measuring it doesn't make much sense to me. You should choose a colour space that is at least large enough to contain all the colours as originally captured by the chip. Setting a colour space in the camera is of no influence at all, except that some RAW converters will read the setting from the exif and automatically convert into Adobe RGB 98.

Saying how much you have been impressed by Sony's DRO, while you also say you always shoot in RAW does not make you look very smart. DRO only works for JPEG conversions, or instructs Sony's RAW converter to make certain changes automatically. There is no effect on the RAW data itself. These changes could be made manually with any RAW converter, only most likely at a much higher quality level.