I think the repeating morning / afternoon concept has some merit, but
people would need to be assigned to the morning slot or the afternoon slot
on any given day to keep the room sizes reasonable.  Hard to enforce but
necessary.

Maybe there is a big get-together.  Maybe not.  Maybe the smaller
get-togethers that having so much "non-presentation" time will create are
more worthwhile anyway.

If you are giving one presentation, giving it twice either on the same day
or on another day that week is not what I would call overtime.  Especially
if you don't miss any other info.

You could repeat the conference at a totally different time of year ...
everyone who didn't get in is automatically registered for the second
conference later that year ... kinda wacky but ...

You could plan for a second conference of the same size in the same city
(different hotel).  After presentations for C4L1 are finalized, presenters
are sought on similar topics for C4L2.  Overflow registrations for C4L1
automatically go to C4L2.  Similar content means that institutions who paid
for you to come to learn about X will hopefully not be upset if you learn
about X from a different person across the street.  Everyone hangs out
informally during off-presentation times.

One could call that "tracks" but I'm trying for more of a "mirror download
site" concept.

Or ... you just go Big and you accept it and then you think about how to
have other conferences (maybe regional, maybe not) that are Small.

-- Susan