2003 Dodge Ram 4.7. Just had my oil changed saturday and the guys came in to show me the exact same thing. Owner said he has had the same thing happen to him. He said he would recommend changing the oil again after another 1000 miles and putting something in it to clean out the sludge.
I make alot of short trips myself. Put maybe 10 to 15 miles on the truck a day during the week.

 

I should have mentioned I am concerned it's a head gasket. It seems like an excessive amount. But the design is such that I can see it allowing the sludge to build it's way up the plastic tube to the cap.

 

If it's a head gasket leak you'd be seeing signs of coolant in the oil from the pan and not just up in the neck. Also because the coolant is entering at the cylinders, it's almost always accompanied by a misfire code...

 

I dont think (I hope not) it is a head gasket leak. I figured out where my coolant is going - right under the rubber flooring on the passengers side... Time to replace heater core.