Two things come to mind - gastroperisis OR celiac's disease. As you know, gastroperisis is a consequence of diabetes and I believe the symptoms are a general feeling of fullness or nausea after eating. Celiac's disease is an autoimmune disorder that is commonly seen in people with type 1 diabetes. Have you tried eliminating gluten from your diet to see if that's causing the problem? From what I understand, the symptoms of Celiac's can really vary from person to person.
Incidentally, I did have some serious stomach issues these past few years. While my Celiac's test came back normal and the problem didn't seem to be gastroperisis, my symptoms did improve when I went "low carb" and removed a substantial amount of gluten from my diet (I was eating a lot of bread, rice, and pasta). Also, I had a blood allergy test done that came back strongly responsive for wheat.