Try any Re-Store (habitat for humanity) in your community, they usually have a wide variety of fixtures and other lighting things... good luck!

Rejuvenation

nice lamp!

I've seen glass globes like that at Salvation Army and Goodwill.

Lightbulbsurplus.com. I have found replacement globes the right size on this site, and I thought the prices were reasonable. You might try a Habitat Reuse Center.

I've seen globes like that at standard hardware stores, like Ace.

Have you tried a large lighting store? or even Home Depot?
Glass globes aren't hard to find.

Try School House Electric http://www.schoolhouseelectric.com/ or VanDykes Restorers http://www.vandykes.com/

I've purchased this at Lowes when I broke the one on our kitchen ceiling fan. They have a lot of different options. You could probably get it Home Depot, Ace, etc as well.

Depends on where you live. In the East Bay in California, Urban Orb may have something like that. Locate in Berkeley.

Any additional info would have been helpful - whats the size?
Glass globes can be purchased at any big box or even a local hardware store...

Heck, I've seen those at Walmart sometimes.

I actually have one sitting on my basement currently. I would say either School House Electric, an architectural salvage store, eBay or a thrift store. Just be sure that if you don't have the globe with you when searching that you know the fitter size (this is the measurement of the opening of the glass globe). Good luck!

Third or fourth recommendation for rejuvenation and/or schoolhouse electric.

heres an ebay auction for some hard to find mirrored globes

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=281055097688#ht_3446wt_1398

We just threw out one of these yesterday on a reno job where I work! Dang! But I've seen them at thrift stores all over town, and I'm pretty sure you can buy them new at some hardware/home stores.

http://www.grandbrass.com

Vintagehardware.com, Great vintage style shades and Has all different fitter sizes available.

http://www.vintagehardware.com/vintage-antique-reproduction-slip-shades-bowls.php?cat=196&keyword=2-1/4-inch-shades