6 weight for bluegills?
If you're going to use it solely for bluegills you could use a 2wt, but I think you'd find a 4 wt a bit more versatile.
As to a good source and size, I'd see if you have a local fly fishing shop to help outfit you. In general terms longer rods are more forgiving, but if you're fishing in close confines a shorter rod would be beneficial. I'd stay away from the cheapest combo outfits, I think in the $100 range you can get a nice rod, reels are similar and in the smaller flyrod sizes really just a place to hold the line so going cheap on the reel is a better place than on the rod. Don't go cheap on the line.
Yep.
As for winding up with something bigger than blugill, well it was either two or three years ago that my best bass of the year on a fly rod took a size 16 or 18 Partridge and Olive soft hackle. I was using a 4wt Granger bamboo rod and targeting panfish. It was the closest I've ever been to getting into the backing in the local pond. I did have a decent disc drag reel though.
A much bigger bass did break me off this spring when using a Tenkara rod. It just swarmed up and swallowed the 'gill I had caught, and after it's third "run", the rod was horizontal and the 5X tippet gave it up.
