In version 3.4.0 a new feature has been added that should open the
competing consumers feature to all those not running with the .net
client api (the jvm client will soon have native support as well).
Basically you can use http clients and still get competing consumer
behaviors (e.g. message timeouts/retries/etc).
To get an idea of how things work checkout:
http://docs.geteventstore.com/http-api/3.4.0/competing-consumers/
An existing atom client should be able to support competing consumers
in an hour or two of work.
Cheers,
Greg