The OST is being sold separately here - http://www.amazon.com/Sudeki-Original-Soundtrack-Tom-Colvin/dp/B003JKGN0Y (I wonder if GOG could have made a deal to include the soundtrack if they bumped up the price to $9.99.)

Of course you can always listen to some of the songs on YouTube: https://www.youtube.com/results?search_query=Sudeki+soundtrack

Anyone know if the music can be found amongst the game files?

It would certainly be nice to get the soundtrack as an extra. The problem with upping the price to $10 with the soundtrack is that Steam offers the game for $6 already and fickle users who aren't interested in the soundtrack might go for that option instead. If we could get a "Digital Deluxe" edition with an artbook and soundtrack that might be good. Fingers crossed that we do get the soundtrack at some point. :)