This is a very slick implementation of this sort of thing with dhtml:

http://interface.eyecon.ro/demos/sort.html

It's all much easier and more flexible if we get rid of the 
requirement to allow blocks to be extra-wide. Just having x (still 
configurable) columns, with blocks stacked on each other one over the 
other, makes it much easier to drag them around and determine a sort 
order (instead of the current grid). Also means you don't have to play 
with the length of your task list to avoid wasting space.



Basically, instead of the current grid:



     a | c

     a |

     a |

     - | -

     b | d



Here, "c" has a lot of extra space and "d" is too far down because it 
has to clear "a" as well. I'd propose:



     a | c

     a | -

     a | d

     - | -

     b | e



It also happens to simplify the code a lot, of course, but that's not 
the main reason to do it. The only real bummer with this change that I 
can think of is comics - but I'd just have one extra-wide column in my 
portal to accomodate that; I personally don't think it's worth it just 
for that.