There are quite a few out right now, not mainstream though and really not polished.
A bunch are coming out soon including the Galaxy Tab which is getting lots of press but it is only 7 inches and will be expensive.
here is a cheap one ($260) that is out but would need some hacking:
http://www.zenithink.us/zenithink-zt...Fdj75wodvxHFGA
And this Archos 10.1 looks good (about $300) coming soon. (sept or oct)
http://www.archos.com/products/ta/ar...try=us&lang=en