With the release of conduit 0.3., it looks like the conduit dependency is out of date and requires more than a trivial version bump.
conduit 0.3 and conduit 0.4 (to be released) are not being widely used yet, that's why aws still has not moved on. A good thermometer of conduit's maturity is weather yesod has been released using it =).
I'll keep this issue open.
I would be in favor of waiting until the conduit/pipes debate reaches some resolution and then just upgrading once.
Right, I also have problems with my GHC installation now, so I can't investigate how much would need to be changed right now.
Fixed by #19