I thought it could be digestion too but it started in August 02 when I believe I was in a celiac disease crisis. I thought after going gluten-free the noise would have gone away but it hasn't. I have been gluten-free since Sept 03.
Yes mine is in my intestines, not my stomach and it's pretty loud!
I was my own walking slap stick comedy for five year olds--really lound, very gasey (but not gas) sounds. Very embarrassing. I"m just now getting diagnosed with Celiac, but in 2007 I cut out dairy and those sounds that plagued me since I was a kid, have almost disappeared. I only get them when I let myself have ice cream.