My HT is along a wall with stairs along one side that go up to a loft above the living room. There is a landing about 5 feet up that I thought I could put a second sub on. Would this be a bad place for a sub? There are about 1 inch bars spaced every 4 inches between the listening area and where the sub would be. I was thinking either a SVS SB-2000 or possibly the PC-2000. Maybe I should just find another spot if I go with two subs.

The bars shouldn't make any real difference. If you try that spot I'd suggest moving the sub as close to the near edge of the landing as possible to avoid reflections from the landing floor. Whether the spot's good or bad, no way to know, you'd have to try it.