Framing basement wall without covering top plate and rim joist
House was built in 1951, concrete block walls in the walkout basement. Walls are bare, I want to frame them and insulate, but I want to leave access to the top plates and rim joists. The reason is that in the past two years, I've had carpenter ants twice in the rim joists, in wood that was not ever wet, just areas of penetration for electrical and plumbing. I probably wouldn't have found the carpenter ants for a long time had the joists been covered by conventional framing.
Is there way to frame that accomplishes this? The typical framing method, namely nailing the top member of the new wall directly to the bottom of the floor joists, can't be done.
What about lowering the top member to the height of the block wall, then adding a spacer block of 1.5 inches thickness, to span the distance between the top member and the floor joist? This still leaves access to both the top plate on top of the block wall, and to the rim joist.
Or is there a special type of bracket that would accomplish this?
Any opinions appreciated.