You want to be careful with the amount of padding.
I think there are still rules regarding layers, so if your jersey has lots of padding on the arms, you won't be able to wear elbow pads.
The problem with this, is that no jersey offers as much protection as elbow pads do, so your losing out.
Eclipse jerseys (at least the 07 ones) have thin padding, but it's there.
It isn't enough to get you pulled when wearing elbow pads though.
You are also looking at the quality of the material and stitching etc.
DYE, Eclipse and WDP kit has always been very good.