Thanks for sharing this!
With the mantl project https://github.com/CiscoCloud/microservices-infrastructure we feed mesos task information into consul.
We've looked a lot a load balancing and feel that rewriting haproxy files dynamically can lead to brittle behavior.
Our current setup is we use traefik https://github.com/emilevauge/traefik to proxy marathon tasks.
Haproxy 1.6 includes some dynamic dns lookups http://blog.haproxy.com/2015/10/14/whats-new-in-haproxy-1-6/
