The iConnectivity 2+ we reviewed in our Sonic Touch show blew us away. The only solution for getting iOS audio into the computer directly and allowing integration of the iPad into an existing setup together with MIDI integration is nothing short of groundbreaking.
However, we have been pining for news of the much delayed iConnectivity 4, which lets you hook up two iPads (or other usb audio hosts) routing their audio to another computer via aggregate audio on the Mac (native on the PC). It also boasts 4 MIDI io ports and a network connection for RTP MIDI - allowing direct MIDI over an existing network. $199
News is that its at the factory and will be shipping real soon.
Also on display was a prototype of the iConnect Audio - which combines the features of the other devices together with a 4x4 audio interface with mic preamps. This dispenses with the need for aggregation as it can act as your sole audio interface.