Well, it's not as I remembered, anyway. Auto layout seems to just leave everything in a single column with scroll arrows -- the height of this seems to be calculated assuming 480px screen height, so it scrolls unnecessarily in portrait.

Manually setting the layout to 4 columns, 6 rows, makes my 12 test items fill 6 rows, but only two columns. This works cleanly either way, since it's less than 480 both ways. When setting it to 3 columns, 3 rows, it fills 3 columns and 4 rows, which also works. Setting to 4 columns, 3 rows, it does just that, overflowing in portrait mode, but making an appropriate "best-effort" fit by sticking to the left side and overflowing off the right. Forcing to 1 column makes it overflow the bottom of the "screen", with scroll arrows, but again this stops at 480px.

(And I'm not sure how much easier to populate it could get -- unless perhaps I'm running an extras-devel version with that feature already live. The configuration I'm seeing is first-rate.)