Hello, guys! I'm longing for the Linux version too since I've completely missed the said event. Trine is a wonderful game, I tried it in Windows and will surely purchase it for "the alternative platform".
I believe that (finally) the time has come for a revolution in media distribution, and "the last" companies have great chances of becoming "the first". I may be wrong, but the very results of the HB show that the opinion of Mac and especially Linux users being poor/greedy/only intrested in compiling wine
is nothing but a crap used to hide secret pacts with MS (or mere lazyness).
I recently had to buy a Windows copy just because this summer is a nice time to play Witcher 2, Portal 2, etc. In this situation the OS is treated like a game emulator worth around $100 (2600 RUR).
(Sad but true)
Ubuntu Software center is a nice place to start, but don't forget about the alternative channels too, since it must be available for all modern distributions. By the way, Steam works well in Wine, and maybe if around 10 modern games are ported to Linux they will compile a version for it. Dreams. ^^'
So, you are doing the right thing, good luck to you, and who knows, maybe the others will follow your path soon enough.