How can you keep a stack of Swedish pancakes fresh?
You have this same problem with most fried foods that you want to serve fresh. Anyone who makes latkes for Hanukkah knows this problem well. So it's similar to this question What technique should I use to make latkes for a party so that I don&#39;t have to stay in the kitchen?

You can try what I do for latkes - I put them on a drying rack, sheet pan, skillet, etc. in the oven set at around 250°F. You may want a lower temp for Swedish pancakes, like 200, since they are less dense. They will not be the same as fresh from the frying pan, but they will stay warm and crisp. 

For reheating, put them in a dry cast iron or non-stick skillet or in the toaster oven on 375-400 for 4-5 min, more or less time depending on thickness and initial temperature.

If you do this a lot you could also invest in a heat lamp/warmer set up like they use at fast food chains to keep the fries warm. Cheap one on Amazon - http://www.amazon.com/Home-HL100SV-Culinary-Heat-Lamp/dp/B0043M5N08

Many a Top Chef participant has been felled by this problem though - fried foods, blinis, etc. are never the same as when taken out of the fryer fresh, but they are still quite good out of the warm oven.