Skittycat
I'm fairly sure "-chan" has something to do with being small/young/whatever. I've seen it translated in manga before and I've heard people using it and in the context it sounds like it means that...
Ahhh, but we'll use this why don't we. An example? In Slayers NEXT, Lina calls Aunty Aqua "Oba-CHAN" if it meant little then Aqua would be younger than Lina, and that doesn't make any sense at all.
blaugh Furthermore, even if we did use your logic, then Lina would be saying "Younger/Smaller Aunti" and Lina has no right to call anyone small. And I don't think that an "aunt" would be younger. (although in some cases they are, don't get me wrong.)
xd (Yes, I've had Japanese lessons)