Hi - so I know this is nuts.

If we start with a couple premises for the code4lib conference:

1.  Single thread is crucial.
2.  250 is about the top limit of a single threaded conference.
3.  400+ people want to attend.
4.  The conference takes 2.5 days.

What if we ran the 2.5 day conference twice in one week?  

1.  Session 1 runs from Monday until noon on Weds.
2.  Session 2 runs from 1p on Weds until the end of Friday.
3.  Every one of the 23 accepted talks is given twice, once in each Session, in the same order.
4.  Each Session is attended by a different set of attendees.

We could serve 500 attendees this way.

If everyone came for the week, there could be parallel seminars, hack fests, BootCamps, THATcamps, CURATEcamps, c4lcamps, etc... for the half of the 500 that wasn't in the main conference.  People could also just decide to come for the 2.5 day main conference, I guess.

I SAID it was crazy.  ;)

D