Already possible
I use my iPad now on my B&W Zeppelin system. Works fine and looks good too. The Zepplin's clever future proofed doc allows for any size of device that can balance.
There are more speaker systems available for the iPod and iPhone than I can count, but the iPad has missed out on all the fun so far because, of course, it’s far too big to fit into a docking system designed for its smaller brethren. iLuv iMM747 iLuv's iMM747: jumbo dock? I’ve heard rumours of a couple of iPad speaker …
I use a Yamaha PDX-50 wireless "dock" with my ipad, and it makes an excellent flexible system. It won the award for best iPod dock system in "What HiFi'" a couple of years ago and is available for about £100 now.
It uses a small transmitter that plugs into the dock connector. The iPad can then be used in landscape or portrait mode and the speaker box can be placed where you choose without taking up space next to the iPad.
It works superbly for me...