Reddit mentions of Seven Brothers

Yeah, as far as I can find, they've been published in english only in 2001 by Aspasia Books, a little Canadian publisher. If they don't bundle it, it's hard to imagine you could find it anywhere.

As for finnish lit, the grand daddy of them all, The Seven Brothers (there are two translations, and the word is that the Impola one is better than the Matson one) is a fun read and a great look into the finnish psyche but I'd imagine it loses a lot in translation - like Linna's work as well - due to the amount of cultural nuances, dialects used and such. It's a relatively common complaint about translated finnish literature, it never just seems to come out right. Way back when, Linna even sued the American publisher of The Unknown Soldier and got the translation off the market..

For something that translates well, you could go for The Egyptian by Mika Waltari which is a story about ancient Egypt so Finnish cultural norms don't get in the way of storytelling.. If you really want to get into it, you just have to learn the language. Many of the classics remain untranslated and some of them seem almost untranslatable (Alastalon Salissa!).