Straight answer is "No".
Dedupe work on volume level and not on aggregate level, however if you are using provisioning manager to create your volumes you can configure the provisioning policy to enable dedupe and set the schedule so whenever you create a volume you don't have to set dedupe.
To answer your second question about future plans, I am not much specitial sure as no one is talking about dedupe at aggregate level though dedupe volume limit is suppose to be increased in following release.
Cheers.