Check for some C-record era Campagnolo. Velobase shows ~41.5mm. I also love the look but I have a bias for that era. I'm also running an Ofmega Master on my Trek right now, similar looks, listed as 43mm if you Google it (and I think it's about that, I can measure if you like)
VeloBase.com - Component: Campagnolo Athena
VeloBase.com - Component: Campagnolo 304/104, C-Record
VeloBase.com - Component: Ofmega Master