Yup, I agree. The XB1000 was so much wasted potential. It came out sounding like the weakest in the "Extra Bass" line. Imagine if Sony re-tuned them to be even bassier out of the box, with a slightly more V-Shaped sound with better extension in the highs. I think they would sound great!
I got them at Sony Centre (2nd floor) at Sim Lim Square. All the major Sony stores were out of stock (Bugis, Wisma). I was quite fortunate to find a place that actually sold them.
Out of the box, and from memory, the XB700 has more bass than the XB900. Still, I will definitely need to take out my XB700 to have a good comparison between the 2. I might even do a shootout between all of my XB cans - XB200 to XB1000. That would be fun for a basshead!