I live in the EU (The Netherlands to be precise) and a little while ago I finally decided to make a US account. Nothing at all to do with being jealous how much more nice stuff US people get (for less money! gasp) at all ;)

What I was curious about. If I download an XBLA game that isn't available in the EU (say.. Trenched) or Xbox Indie games which are completely not available in my region. Can I aside from play the demo on my EU account also safely buy them and then play them on my EU account? Or is Microsoft very strict on this and do I run the risk of my EU account being banned or something drastic like that?

(I just want to play Techno Kitten Adventure like Jeff did a few weeks ago damnit! :p)

I think you can play it with your EU account as long as the US one is still signed in (maybe with a 2nd controller?) 
 
Is that right? As for repercussions, who knows, MS can be jerks sometimes so... But I really doubt they'll punish you for that.

You can play them without problems, it's like your normal account bought them. 
I guess it can get a little complicated when you use the "recover account" option because all these games are attached to the accounts that bought them.
You can also buy DLC with different accounts, we have to do that here because Gears never came out so there is no DLC available.
 
For downloadspeed I would rather choose an UK account, though. And the Indie games are available in many countries, Germany would probably even better for you.
 
edit: Sometimes, content is locked by your IP, though. So we need to use VPN for the Gears DLC now for example, even on the US account.

The content is signed to both profile and console, meaning that you can use any content downloaded on that console with any other profile. I've been thinking about getting Trenched via my US account also.

So no risk that Microsoft would look down upon this and ban your account for it?

@mnzy: I originally made one to use Netflix. For that you also need a work around to go around. The easiest I found works through a DNS redirect. I'm not sure if it's legal to post about that stuff here however. But if your interested let me know through the mail system here. It's quite fast and takes minimal effort to use I found. Less hassle then a VPN.