So can anyone tell me is the Twin Shadows Expansion out of print? If so, how hard is it to be found?

Twin Shadows seems to be in stock in our Finnish shops, so look around.

(At least it's not on the reprint queue yet.)

I got one from my LGS today, they ordered it through normal channels.

It looks pretty expensive online right now, which can be indicative of a shortage.

FFG is pretty aware of which of their product sells and are good about keeping things in stock, or atleast, reprinting. If things are selling for more than their MSRP, just wait for the reprint. I know it can be hard, but hang in there, it will come around.