(quick response appreciated): change to box-packing algorithm?

Hey, what do people think of changing the packing algorithm from:

  "a box will be placed as far up and to the left as it can fit"

to

  "a box will be placed as far up and to the left as it can fit and
   still be no higher above and no farther to the left than its
   preceeding sibling"

I need to do this in order to be 100% independent of the number of
columns/rows (ie so you can set parent.rows=10000 and child.rowspan to
1000 and still get great performance).

This also happens to be the exact same packing algorithm used by text
reflow...

  - a

-- 
"It's lucky," he added, after a pause, "that there are such a lot of
islands in the world.  I almost envy you, Mr. Watson."

                                                   -- Mustapha Mond