Loopy working with the Audiobox iTwo interface (Presonus)
I'm using the iTwo to record guitar or voice into loopy (though I'm mostly sure both could be recorded together at the same time as loopy had switches to indicate whether it should record sound from the L, R or L+R channels). Ask me to try, if you want to be sure.
Though there is no hint in the documentation of the interface, I can attest that loopy can be controlled from a midi pedal board connected to the iTwo interface via DIN connectors (midi in and out). It's a must-have for us guitarists as our hands are already busy on our favorite axe usually
When connecting the iTwo to the iPad, the output of the iPad is sent back to the interface, to which you can connect both a headphone and monitor speakers. There is a button to control the mix between the sound coming directly from the instruments and that coming back from the iPad (eg, sent by Loopy).
The iTwo suffers from being not powered by the iPad (I guess like other interfaces), so you need to power it up via a regular USB plug. But buying a USB battery for charging phones should be ok. This reduces the number of power plugs you need, which might be important when playing live I'll post on that later to confirm the iTwo can be operated in random places (I ordered a battery recently).