You could just use a Lenovo X-series tablet that's been around for years, runs PowerPoint and every other Windows program, has a fold-out full-sized keyboard, and already connects to existing projectors and printers without dongles.
Lenovo X-series tablet - Starting model price: $1879.00 (currently on sale for $1399.00).
Apple iPad - Starting model price: $499.00.
I think it does not matter whether the Lenovo tablet is more fully featured. People will buy the iPad without a second thought, because it is affordable, and then make it work for this purpose.
Additionally, and I hate to admit this, but the iPad will probably have greater fashion value to be seen with in a boardroom than the Lenovo tablet.
