The CP-251 gives you one 4-way multiple and the VX-351 gives you two 4-way multiples. So, with both units that gives you a total of three 4-way multiples. Now, there are 5 Moogerfooger effects. Basically the bottle neck is that I don't "need" another CP-251, but I do need more 4-way multiples. The idea of buying another CP-251 and getting only one 4-way multiple stinks (I know the added features of a second CP-251 are nothing to sneeze at).
So, here's my idea


Alternatively, Moog could use a single space 19" rack mount with a CP-251 style LFO laid horizontally and four of the 4-way multiples to make a less expensive yet still powerful Moogerfooger multiplier. I think it's important to keep the design simple since the VX-351 and the CP-251 already have all of the CV features.