This guy out in Vancouver is making clothes specifically for tall slim guys. I've tried some of their stuff out and it is really high quality and fits great (I'm 6'7" and 215 lbs and XLT fits me good). They just launched a kickstarter campaign for their tall slim hoodies. The crazy thing is that they are made almost entirely from bamboo! Definitely worth checking out if you're tall and slim you've had a hard time finding decent fitting clothing.
Tall Slim Hoodie Kickstarter Campaign
Tall Slim Hoodie Kickstarter Campaign