Not /nearly/ as simple as you make it sound, as each of those powersets would have a separate 'draw' animation.
Back when Shields were implemented part of the difficulty was the devs having to go through all melee attack sets and add new animations to work single handed -- and they still had to give up on a few powersets and say "These just won't pair with shields".
I'm not saying it isn't possible, but it's also not as simple as you're making it sound.
My characters - all on Virtue.
Gabe's Internet [censored] Theory
RMT spammers WILL steal your credit card.
Suggestion - For ranged damage dealers.
The age old suggestion, here again because I had a whim.
One hand pistol - range primary, One hand weapon- melee secondary. We've got models that'd work on both, now just a production cycle an we'd be set =p. You know you want your gun .
Pinnacle & Virtue:
A bunch of Heroes - Alpha Team, Legion of Order.
A bunch of Villains -Black Citadel , Pinnache.