It was going to happen sooner or later. The new wireless Intuos4 is the same size as Intuos4 M just with bluetooth. There really isn’t much difference compared to the regular wired version. The wireless version has built in battery. It will last for around 7 days with full use or somewhere thereabouts. when you do need to charge it, just plug it into any usb port on your computer and it will charge while it is still in use.
The wireless version is good for those that hate wires dangling around or for those that have pets ( more specifically cats) who like to chew on those cables. If you’re interested in this, the Wacom Intuos4 Wireless is available now for around $40 more than the Intuos4 M (5×8). Please note if your computer doesn’t have built-in bluetooth, you will have to supply ( or purchase from Wacom) you own bluetooth adapter. Check out more info at Wacom.com.