If you haven't already seen it, get and watch a copy of Benn Karne's "Bonneville Wide Open". It features Jack Costella's 5050 yellow lay-on-the-belly liner bike, and show it - and Jack and rider Andy Sills -- going through tech and working with the officials to get the safety harness all worked out. I think fire suppresion was also mentioned in the BWO video.
And once you've got an idea of the hassles -- get in touch with Andy and also with Erin Hunter. Both of them piloted the bike - both can give you first-hand comments on the belly-down situation.