Another solution -- nightgown
I don't know why I didn't ask them before -- I love their T-shirts, but I really have been wanting a night gown ....
Anyway, I finally emailed them and asked about an extra large size cotton nightie. Got it in the mail today and it's great. Both the pump and the Dexcom meter fit in the pocket and didn't fall out when I fed the dogs (one of my big tests).
I'll probably let them continue to run lose when I'm sleeping but it's nice to have a night gown that works.
I think I'm going to order some more stuff from them this evening.