I'm rank 20 and looking for a legion base with high artifact production.

The higher the artifact production from the legion the better. I'm looking for at least 20K AP per day and any research or minerals (I doubt there will be any minerals) are a nice bonus. I will be choosing the legion which has the highest artifact production that will accept me. Bear in mind that I might decide to reset my ship to become a missioner again as I decided to try out being a fighter and am still finding out whether or not it's the style of play for me.

At your rank I'd recommend mainly research, as it is good to have that edge over your other players.
I know you want artifact, but that's the truth. Later on though, artifacts will become a major role in your game, but not atm.

Also, if you consider those words, I recommend Delta V2 to you. They are level 5 with mainly research with some arti production on the side. They'll help you become strong.

They only accept rank 100s now!

The Invisible Storm doesn't quite meet your specs, but we're a new, quickly growing legion with a split artifact/research base. It's just level 4 at the moment, but only energy is needed for level 5.

They need the members, and they already said to TDAL they'll accept the ranks.
<=== One of the main leaders, in the know.

Space Spartans

Level 5 artifact base (~22k arty/ ~ 4k research per day per member)

We are a quick growing active legion. 2 spots open. Come join us!

Try Sons of Talon. They have a level 4 artifact base. They would gladly accept you even if you do decide to reset. Then you have access to all of Talon Faction (Talon Company, Steel Talons and Sons of Talon). Very helpful and fun group willing to help out any member willing to be loyal, including planets, artifacts, minerals and advice.

Though I agree with the rest of the posters about early research. Warp Fleet Lotus is accepting all ranks atm. 50k+ artifacts, 5 days/week even split untill we start to fill up some more.

To the other thing you mentioned. There will rarely be a better time to PVP than the early ranks.