Hi Hot Pink
I have been using the vaseline, it does work well, I do as you said, just apply a very very thin layer and then the shadow on top. So far I have only used it with hi-end shadows, nothing that has staying problems. I like it, and also, it seems to keep my lids smoother, I guess it is the extra moisture. I spent alot of time in the sun and in tanning salons when I was younger and STUPID and my skin is starting to show the effects of it now in loosing it's smoothness. So the vaseline moisturizes under the shadow and my lids don't look as dry or god forbid "crepey"
As I have been trying to switch over to more natural products, I am going to try the "UN-petroleum" jelly you see for sale at Whole Foods and other health food stores. Thanks for the great tip for using this as a base!