Leverage and combine existing camera-in-capsule and helical-tube-moving-mechanism robots to deliver a single final product. Phase 1, just deliver the 3d modelling, tweak the dimensions, deliver 3d file preferably in Autodesk Design 123D and in .stl format (ready for 3D printing). Phase 2 (shall be another budget) involves proto-build-test the robots.
 camera-in-capsule design, http://www.dailytech.com/ColonProb
Note: we shall point you to the small camera and motor and you design the capsule to wrap around it.
 helical-tube-moving-mechanism robots, http://students.iitk.ac.in/roboclu