Do you guys know of an external EQ with mono in - stereo outs?
Simple answer is no as it's an oxymoron, the out isn't (wouldn't be) stereo, just a split of the mono signal, so 2 mono signals. We say the MP1/2 are stereo but it's kind of sudo stereo and introduced at/by the chorus stage in both units (albeit a little differently). So you could say the MP2 fits your description, it has a mono 9 band graphic just prior to the chorus (sudo stereo). Also any multi FX that include eq generally let you use L in mono and have L/R outs, so similar. If there's no difference applied to one of the signals compared to the other, then it's just dual mono (so use a standard stereo eq (which is basically 2 mono eqs in same box) and split the input signal across both eq ins, applying different eq on each signal is now a form of sudo stereo).