There are several Tahoe Hybrids on eBay Motors for sale, so presumably they've arrived at dealers.

http://motors.shop.ebay.com/Cars-Tru...TahoeQ20Hybrid

All are fully-loaded 4WDs in black, scattered across South Carolina, Texas, Indiana, Michigan, and Missouri.

edit - And there's a black Yukon Hybrid in Montgomery, Alabama:

http://cgi.ebay.com/ebaymotors/GMC-Y...em180211959144