Would a heatsink and fan assembly from a cech 2xxx fit? Sony are known to use lower efficiency heatsinks and fans when they reduce the chipset sizes so if one fits it could be beneficial to the console? The 2003 heatsinks look to be better as they use heatpipes and not just a block of finned alloy on the 210x/250x/300x
You could probably pick up an 200x assembly cheaply on ebay so worth looking into maybe.
EDIT ignore what I said, I just tried fitting a 200x heatsink to a 250x and it wouldn't fit