For those interested in bridgmans posts about the hardware, I highly recommend the articles anandtech wrote for the GT200/RV770 launches.
Yes, they support more than 1000 threads.
It's very interesting to see the different approaches ATI and NVidia took. NVidia went with very simple SPs, which are all capable of doing all operations, while ATI went with more complex ones which can run multiple instructions at once - with the tradeoff being that the instructions have to be a certain mix which means the compiler has to be very smart about how to use the resources.
Other GPU vendors use SIMDs in a similar fashion, but without the superscalar instructions.We have multiple SIMDs because even for a single task you need some granularity to handle the mix of vertex, geometry and pixel shader processing.
I guess a someone still needs to write a load monitor for your favourite desktop :D