Could I just put a longer pitman arm on it? The center link slopes up to the pitman arm from the idler arm. Wouldn't a longer pitman arm level things out and give me some clearance?
I think you mean shorter. Your pitman looks like it may be longer than the idler. Yes, a long arm will bring it closer to the torsion bar. Easy check is to take the center link off the pitman and move the center link back the extra inch or so of length the pitman adds and see if that changes up the difference you are seeing. BTW, the longer pitman is the fast ratio style. Old bucks down trick to get this effect is to use a C body pitman. If you had a matching fast ratio idler, you may also seem the same issue on the passenger side to match.
Something I can't tell by the pictures you have is the relative height of the drivers side tie rod end to the height of the pitman arm. The grease cover on the tie rod does not look compressed at all.
But, what problem are we trying to solve here? I thought it was getting the tie rod end to back off hitting the t-bar. We're now talking about changing oil pans, changing pitmans, and even moving the center link.