Good pils malt has it's own unique flavour - you can add other malts but the pils flavour will still be there. You'd get a better approximation using cheap pale malt (2 row) + specialty malts (or other base malts). Or just use the correct tool for the job in the first place!
While I like the theory of this thread, that is what I was thinking. I have been moving toward keeping 3 base grains on hand (European Pils, American Pale, European Pale Ale). I like the idea of just having 2 base malts (or just 1?).
I have not used a lot of Pils in the past, but the Weyermann Bohemian Pils I have on hand now has a significant amount of flavors that I would not expect in a Pale Ale Malt. Briess Brewer's malt also has a straw character that I would not expect in a Pale Ale Malt. I doubt it would get covered up with a touch of specialty malt. Maybe you could find a very bland malt, but I am not sure what...an extra pale malt or a bland pilsner?.