That sucks. It may or may not be related to how the router works, but it's definitely about performance and visibility, which is what this is all about.
Can you email me at adam at heroku dot com and I'll connect you with one of our Python experts? I can't promise we'll solve it, but I'd like to take a look.
I'd be really interested to see some public information resulting from debugging Python apps. We're holding pretty steady, but see a fairly constant stream of timeouts due, apparently, to variance in response times. To be sure, we're working on that. But, in the meantime, our experiments with gevent and Heroku have been less than inspiring.
Can you email me at adam at heroku dot com and I'll connect you with one of our Python experts? I can't promise we'll solve it, but I'd like to take a look.