if you really want an Android tablet....
there are many available from China already.
While some are pretty crappy and run Android 1.5 there are devices like the Weistech A81E that support FroYo and while they are not official (ie Market and the Google Apps are not supported) there are cooked ROMs that add that functionality back in.
Android isn't like Apple where the fanbois have to wait for whatever the mighty Jobs chooses to bestow... like Windows CE (that a lot of these tablets/slates also run) Android is open source so anyone can take a fork and call it a product.
Go check out http://slatedroid.com/
Personally, I'm waiting for a Win7 Slate but that's just how I roll


