Another idea about this,
For n variables,
X1 x X2 x X3 x ... x Xn = X1 + X2 + X3 + ... + Xn
if n is even then {1, 1, 1, ..., 2, n-2} is the solution. eg:
1,1,2,4
1,1,1,1,2,6
1,1,1,1,1,1,2,8
why? Because
1 + 1 + ... + 2 + n = (n - 2) + 2 + n = 2*n
You could also do this by induction on n...