It's a no-brainer for me that proxy armies are an obvious choice in 40k. In an entire fantasy universe with millions of planets there should be possibilities that go miles beyond the limited number of army lists provided by GW.
So I was pleased to see a 'mainstream' blog covering this idea building on the new Space Marines codex. Goatboy over at BoLS provides a number of fun sounding suggestions such as these:
White Scars...I always liked an army full of Horsemen and this would be a great place to start as some kind of Marauding band of Evil Knights. The plastic Chaos Knight set is a great place to start and you can easily add bits to make them more "futuristic" with daemonic steads, evil weaponry and other bits and pieces. Their ability to scout with a Special character could also be used as an Alpha Legion heavy striking force.
Iron Hands... Here you get into the army I think has the most gas in the tank of Counts As. I can see them being used for Iron Warriors because both armies love technology. I really can see people using this as the base army for Adeptus Mechanicus and allying in the Tau to create weapons from the prayers of Mars. I even can see them used as a crazy Death Guard force with their army wide FNP and It Will Not Die on their Characters and vehicles. The Sky is the limit with their chapter set as it feels basic enough to cover lots of options and still give you room to build and design.
Imaginative and independently spirited gamers will of course go far further than this and in that there is nothing revolutionary about these suggestions. To an old fart like me, it's hobby common sense. What really astonishes me, though - and by now it shouldn't - is how dim, ill-tempered, witless, and limiting (I could go on...) the comments on this article are. Never has the Oldhammer spirit been needed so dearly!
I can only daydream that all these tournament-types are visited in the dead of night by the ghost of Oldhammer*, and that he shows them the error of their ways. Because in my hobbyverse, every army is a proxy army, imagined, built and storied uniquely by its creator. Anything else and it's just... a game.
*I realise this gives the impression that Oldhammer is dead. Forgive me. Clearly this is not the case.