Not exactly 70/30 because it's more like 66/33 but a Topas Sport from Rimowa might fit your requirements:



Pretty expensive, it is a Rimowa after all, but convenient and sturdy (on top of being very easy to roll).

The only issue is that they don't make carry-on models, only 89L and 100L. So if you really want a set, this may not be a good option.