Mine might qualify... the center stone is 1.5ct, and sidestones are .15ct each... I really like how they're more of an accent, as opposed to the traditional 3-stone ring look. This pic shows a bit of the profile so you can see the sidestone compared to the center:
I''ve been thinking of this exact same thing! I have a 1.8 carat diamond, and initially was thinking that even 0.5 carat was too small for each side. However, when I looked at pictures I actually preferred the look of a 2 carat w/ 0.25 carat per side.
Here is a link to a lovely ring w/ 0.86 ct center, and I believe 0.12 ct sides. I also tried to attach 1 pic so hope it works!