Laptop for Auditioning Equipment at Dealer?

I'll be getting a MacBook Pro laptop this summer and would like to take it to audition DACs at stereo dealers. I assume you would need some cable that would let you go out of the laptop in Firewire or USB and into the DAC with Coaxial or Fiberopic. Does anyone know how this might be done? I guess I could take my Airport Express and go out of it with Toslink, but I was hoping to avoid going wireless and using the AE if possible.