Chevy was going to launch their 1/2 ton diesel in 2009 and then the bottom fell out, there is much on the web about this.
And Dodge is also about to do something with a diesel, I believe it was related to a Mercedes diesel so that one may have left the radar too now that Mercedes is out of the picture. We will see what Fiat does. If you go to Europe now everyone is driving diesels and this is a good thing because Europeans also like to drive fast.
Not sure that Ford was going to do anything with 1/2 ton trucks. The problem is making them 50 EPA legal (notice if we dropped California they would probably be sold already). And the other issue is that gas prices did come back down. Now people will argue Diesel is just as much but when my wifes car gets 40mpg everywhere and she is a LEAD foot then you still can't argue, especially when this little 2.0 Liter makes 235lb-ft torque at 2000 rpm.