I'm having trouble deciding whether this is possible or just complete madness. Any thoughts?
It's all in how you use the companion serif. If Netto is used mainly for display purposes, then just about any well-behaved serif would work for body copy. If the two are going to share headline duties, then I would consider something sturdy and relatively low contrast (something Dutch, perhaps?), or go for the vertical axis of a Bodoni/Didone.