BugBackToad model by SonK, which can be found at http://ompf.org/forum/viewtopic.php?f=7&t=752
Sun light in an interior space:
3 objects each with a 512 x 512 lightmap.
1st pass, 2640 FG samples: 33 seconds
2nd pass, 4640 FG samples: 1 minute
3rd pass, 8640 FG samples: 1 minute 44 seconds