6-8" wide hardwood pre-finished floors in stock

You've come to the right place.

"In stock" might be a bit of a misnomer depending upon what quantity you need. Other than the mass produced brands, which as you note tend to be 5" or less, flooring mills are unlikely to stock prefinished floors. Buildirect has some builders grade 6" floors. You might also try some of the importers of prefinished floors (Siberian Hardwoods on Hudson st, Exquisite surfaces in the a&d building).

Otherwise, don't know what your time pressure is but one of the local flooring mills (Heritage Wide Plank on LI, Hull Forest Products in CT, etc) might be able to make floors to order in a common species pretty quickly.

http://www.hullforest.com/prefinished-wide-plank-flooring-c-1_17_22_156.html

Thanks NYC sport. I ended up ordering from hull as they seemed to be the most reasonably priced for custom. 6 weeks lead time.

We got our floor from Hull. They were right on time and we had a very large order and not typical stock. Hopefully you are dealing with Jon Ramos -- he is very professional.