I don't yet consider myself an "expert", but have been actively managing a couple of smaller ponds for several years and have some experience with overpopulations of panfish (usually here in Iowa it's an overpopulation of bluegill, though). First, I would think that adding bluegill - hybrid or normal - will pressure the sunfish population because they will compete for the same food sources. However, even though this may reduce the sunfish population, this will still mean lots of panfish, rather than the more sporting fish you seem to want.

I would instead be happy that I have a good base in the food chain and add more predators to eat these little fish up and grow large. I know for a fact that catfish of all varieties LOVE to eat green sunfish - it's one of my favorite baits to use to catch them! I also catch bass when fishing with sunnies so I know bass like to eat them too.

So I would suggest that you either add another predator species that you always wanted in your pond (maybe smallmouth, stripers or wipers?) or go catch some nicer cats and bass locally (maybe using your sunnies as bait?) and put them in your pond. I would also suggest that you tell anyone who fishes your pond to throw out every sunfish they catch in the meantime.

BTW: If you want to intentionally target the sunnies, think small. I use a lightweight pole and reel, 4 lb mono, tiny painted jig-heads (1/32, 1/64 and even 1/80 oz. jigs - some bare and some with feathers, etc.) and tip them with a wax worm or a small piece of earthworm less than an inch in length. Put this under a small regular bobber, or better yet a slip bobber rig with a small split shot and you'll be surprised how much fun you have catching the little buggers. If you can't find that small of jig heads, a friend of mine just uses a really really small hook, small split-shot and the same bait setup under a bobber with good success.

Hope this helps.