Attendee checkbox layout

I would love to be able to have multiple columns of checkboxes for attendees, or some other way of compacting the vertical space used by attendance tracking. I currently have about 500 (probably more) users that I need to be able to mark attendance for, and the list is is very, very long for scrolling - several screens.

Ideally I'd like to be able to skip about in the alphabet easily, but this seems like it would be harder to implement than just allowing multiple columns for the attendee list. I know that might conflict with the flexibility of being able to compose whatever fields you wish to display based on user profile fields (which is a really great feature) but I'm willing to deal with some truncation in the attendance entry interface in order to have half or a third as much scrolling. Another solution would be plugging in some method of searching or filtering the attendees, but that also seems more complicated.

Thanks for considering the suggestion!