Other than thinking of buying (and trying before) one...?

Not yet.

The problem will all current tablet products (with good tablet interface) is the non-existent multiuser functionality... Simply having multiple user profiles secured with passwords you need to logon after device start, and I would instantly buy this device...

Though as it looks like currently, the first one to provide this would be Windows 8. And I'm not counting some crappy x86 Tablets with shitty build quality and the need of fiddling around with some custom Ubuntu/etc. installation.