I'm interested in this too, but I just wanted to point out that "in vivo endoscopy" is a ridiculous name. Isn't all endoscopy in vivo? "in vivo microscopy" might make a little more sense.
I vote no. The gastrointestinal system is a tube that is continuous with the external environment (like the hole of a doughnut, as they say). Its contents are effectively outside the body. To get in vivo one has to image or physically penetrate tissue.