From Amazon sampler: Passacaglia by Bear Mccleary from the Battlestar Galactica S01 CD.
I’m sure there must be some longer classical pieces that are similar. Can anyone help?
You’re looking for **longer **pieces like that??? 
(Actually you could just play that part, over and over.)
Not classical! You want some 20th century minimalism, my good man!
Try Phillip Glass’ 1000 Airplanes on the Roof. Lots of other Glass would probably fit the bill as well.
I refer to the same sort of “feeling” in the piece. Strings playing like that. Bach for example brings a similar sort of “feel” to it. Essentially I’m looking for Classical music with lots of strings and having a similar melancholy yet not sad feel to it.
Pochaco: Interesting. Never heard of that style. Thanks for the intro.