I bought the Vastex numbering system. It's very nice. But not ideal for us. You are also locked in to one numbering style.
We cut our names and numbers with vinyl in-house and heat press them on.
Plastisol numbers are cheaper, but we do a lot of unorthodox fonts for the numbers.
As far as the 2 color stuff, we'd be in the same spot as you as I'm not sure how we would handle that.