Check out your swingarm pivot, and all your rear linkage. Make sure your fork tubes are tightly clamped, and both flush with the top of the triple clamp. Have you checked your front and rear wheel bearings? My SV would just about drag me across the center line the day the speedo magnet let go on the left side and loaded the bearing with iron oxide. Check your brake calipers and discs and make sure they are tight (OK grasping a litle there, but we're already in the floor, right?) Has your bike ever gone down with any forward motion? Another thought: could your steering head be too tight?
If that don't find 'er, we'll think about it again!
I have Commanders (not II's yet) and run 38 in the front and 40 in the rear, and find them to be awesome. II's will absolutely be my next set of tires. Don't think ya have anything there.