a 2 track recorder of any sort and a feed from the board. a soundguy willing to give you feed from the board. open outs on the board itself. or if you hire a soundguy with a split snake he could send it one way to his 24 track or whatever and split the feed to the house engineer so you don't get the house EQ in the recordings.
don't forget if you take the house main feed you are getting post everything so any changes in volume or whatever will show up in the recording.