I've just completed the above mentioned build. It's a 40 hole XT tandem hub to Velocity Fusion using Dt Swiss db spokes. It is for a racing-style tandem. I laced it four cross because we didn't have the length for three cross in stock. Now someone has mentioned that would be a bad idea, since the four cross lacing makes the wheel weaker laterally and with the extra forces involved, seeing as this will be a racing tandem, the wheel could buckle. At least sooner than were it a three cross lacing.
What do you think?
Ps excuse the typo in the thread title