I run all my build grid in an AWS VPC.
The good folks over at AWS added a new feature (recently? New to me anyways, I just noticed it) called Placement Groups. http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/placement-groups.html
I am lucky enough to meet all the requirements to use it, and it would be nice if TC allowed me to set the placement group when launching instances.
Thanks, and y'all rock. TC is incredible :)