Unknown number of arrays as argument to VBA function

Next idea is to try declaring a final argument (or maybe the only argument) as a paramarray (see VBA help for the function statement):

function smatrix_c(paramarray arr1() as variant) as variant
...
end function

I have never used paramarrays like this, so I don't understand the details of how they work. It does seem like the closest thing to what you are asking for.