MOTM

paul,
depending on what the "module" / "effect" is, for me, a "standalone" 1ux19 
unit would be attractive. however, i don`t have an investment in framing, 
etc. for your existing module line. i would suspect that the majority would 
prefer something styled to fit in with their systems. since i`m planning on 
getting a 420 anyway, ultimately the choice of "whether to buy" for the new 
device would depend on what it did. so, in the interest of peace and 
conformity, i`d have to say that you chose a size / form factor, so stick 
with it.
best,
dave