How about the 1" x 36" belt sanders?

I did mean spindle sander.  I can't answer oscillating or straight spinning as I don't use one.  Ask the bowyers what they use to shape the bows.   
The biggest thing to remember no mater what you use is don't stop...smooth sweeps with light pressure.

Do you run the glass parallel or perpendicular to the rotation of belt? Thanks again!

I run my bow limb perpendicular to the rotation of the belt and I just run it on the edge of the belt.  If I run it across the entire belt, the belt want to grab the limb.  The rubber backing helps absorb the pressure applied to grinding the limb.  Slack belt want will just do the edges of the limb and a hard platin/surface is difficult to keep the limb from rocking from edge to edge thus causing gouges in glass.  I wouldn't be able to grind smoothly with a 1 inch belt.
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Tippit,
My belt sander is loaned out at the moment, but would a setup like this work? Like the red arrows show, pulling the bow towards you with the belt rotating away from you.
It seems like the bow limb slides real flat against the aerosol cans which are about the same size as the rolls on my sander.
You have a nice setup there, but I feel if I went horizontally like you show without a nice polly-v belt backing, my steel platin would make gouges in the glass.
As always, your advice in greatly appreciated.
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Bob,
That looks like it will work fine.

PS: For me going perpendicular is more like grinding a knife which I'm way more comfortable doing.

What is your thought on using a drum sander v a spindle.  It would seem if the speed is slower, it would be better on the hard glass. Is your knife grinder, variable speed, or single and what is it rated at?  I think it might be easier to maintain consistent pressure if the bow is supported on a flat table with a spindle sander.

I think a drum sander would be fine. Variable speeds are much better. My knife grinder is variable and I run it at 40% speed.