I am 5'8" with a 30" inseam and can flat foot the bike when stopped. It helps that my considerable weight helps bring the bike closer to the ground. My Russell seat changed that when it raised me an inch. I'm not uncomfortable with the new seat height so I haven't needed any of this but I've collected the info from friends who have lowered their Concours.
Some owners raise the forks through the triple clamps but I wouldn't recommend doing it by more than an inch, if even that much. Too much, without lowering the rear to match, will change the front end's rake & trail, make her twitchy and prone to tank slappers. Backing out the fork preload adjusters (or decreasing the fork air pressure in the pre-94 models) will also lower the front a bit but limits the range to which you can set your sag. Raise the fork tubes before doing this but do it in small increments to minimize the affects to your geometry. Any ride height changes should be made at both ends of the bike. Remember that lowering the bike will reduce the ground clearance, increasing the chances of dragging hard parts while leaning.
The rear can be lowered some by decreasing the air pressure in the OEM shock. Gary Murphy is a Progressive Suspension dealer and sells their 420 shock absorber. It's available with a shorter length piston rod that lowers the rear. There are other shocks with this feature too. Lowering the rear will cancel the side-affects of raising the fork tubes. http://www.murphskits.com/rear.htm http://www.hyperprousa.com/home.php http://davequinnmotorcycles.com
WARNING: Lower the bike too much and she'll stand more upright when on the sidestand. The odds of a tipover increase the more you lower the bike. The cure is cutting a section from the sidestand and rewelding it. Lowering also increases the effort needed to place her on the centerstand. Again, the remedy is to shorten the legs. Any of these mods, alone or in combination, should lower the Connie to suit you but beware: Too low and halfway through that fast sweeper or emergency maneuver and a hard part like the exhaust will touch down and jack a tire off the road. Think any mods over and chose carefully.