I just bought some Elco paper today, so I searched for "Elco" and found this thread.
There is a stationary shop I came across today in Vienna that sells the entire line of Elco writing paper and envelopes -- including the large cards with deckled edges and matching envelopes, in white and cream. They even have a line of envelopes where the packaging is illustrated with a FP nib -- indicating that they are guaranteed not to feather with fountain pens. I bought several packs of different papers, around 3-4eur each, plus a pack of envelopes.
The paper is great! It is thick, luxurious, and not like any other paper I've tried before. It is similar in density to Clairefontaine, but softer and not slippery. It is similar in some ways to Crane's, but without the texture (my pens hate Crane's texture). The three kinds I bought are: velum finish A5, silk finish A5, and A6 cards with deckled edges. My pens love them all. I think I've found my writing paper!
The shop is called Stoeger
http://www.stoeger.net/nustoeger/papier_1/Papier_1.htmlI think that they would be able to take an order and deliver abroad.
QM2