I'm doing this now with an iPad 2 > HDMI dongle > BlackMagic Intensity Shuttle > USB3 on ASUS G55VW Laptop. Jailbroken with DisplayOut app set to 720p. Visual toys, games, camera, sketchbook... It's DOPE!
You need to trigger the clip in the Monitor page of AirBeam Pro to get the Syphon option in Resolume.
Also note that you can have more than one device broadcasting at the same time and you can choose the source in Resolume (see pic below). But remenber same as above, you'd need to trigger all the sources in AirBeam Pro for them to be available in Resolume.