Clip a wall to a 6 or 7L pole I'm planning on making a wall 6 bricks tall. The wall will have some vertical clips coming out to clip to a vertical pole.  Unfortunately, the only 6 or 7 length bars appear to have the little stopper knubs on them and I think this may interfere with the design. Is there a way to connect two 3/4 L bars together?
You might want to look at Flex System tubing. It comes in a variety of lengths (including 6L and 7L) and doesn't have a stopper.

For what its worth, this is the technique that Jamie Berard used to create the downspout on the apartment in the Pet Shop: