Another idea: define {to'e broda}, where broda is a measurement unit, to mean {broda te'ai ni'upa}; i.e. the reciprocal of the unit.
Thus {to'e snidu} = s^-1 or Hertz, {to'e mitre} = m^-1 or diopter. Philosophical basis is that now these units are no longer measuring length but shortness, in time and in space respectively.
So now miles per hour is {lo pi'ai minli to'e cacra}. {pi'ai} may be droppable from all but the most technical contexts: just assume via convention that when we put two measurement units in a tanru, we intend to multiply them. Then we can possibly build the lujvo {minlytolcacra} (though the La Bangu project does want to avoid proliferating lujvo). This possibly fixes the problem that existing measurement-combination lujvo such as {cacryminli} have no standard as to how they should be constructed.