A couple things:
I have run up to 42mm tires on Deep Vs on my tandem. Ideal? No, but it was fine.
Modern rims with wider profiles will let you run lower pressure. Archetypes are great.
I build some SS wheels with some Kinlin XR22T rims and they have been awesome with 38mm cross tires.
I bought the rims here
Kinlin rims with 45mm tires:
