Just check Wally World online and they don't list any bags for motorcycle ... at least that I can find.  I do remember a display (a VERY small one) near the automotive section where I saw some Bell helmets.  Didn't pay much attention though.  Will have to run back up there and check out the bags.

The thing with magnetic (and all) tank bags is that you have to keep the tank clean to avoid scratches.

As for me, I have two -- first is a small Marsee Bullet Bag.  It'll hold a digital camera and my sunglass case.  It does have a plastic "window" for a note card or directions.



And a basic cargo from Cycle Gear:



No map window, but it holds quite a bit more -- especially with the expansion gusset unzipped.

And neither one covers up the speedometer!