Amplifier manufacturer Hughes & Kettner have announced the WMI-1, a MIDI over WiFi interface to connect an iPad with their amps. The WMI-1 creates its own ad-hoc WiFi network, so you don't need to run it through an additional router. WMI-1 will be available in June, but a price is not given.
http://hughes-and-kettner.com/de/products/grandmeister/wmi-1/