Is it possible to add a "cumulative" column in column view?

[Marcin Borkowski]

Hi fellow Orgers,

I started using column view recently, and I would greatly appreciate it
if I could add a column with "cumulative sum".  In a less-than ideal
world it would be the sum of all the values of some property until the
current row.  In an ideal world, it could only count values of some
property A for rows in which property B is set to certain value.

I looked at the docstring of `org-columns-summary-types', and it is
obviously impossible to do it with it (the `summarize' function always
gets all the values and doesn't get the row number on anything like
it).  How difficult would it be to extend it?  (A cursory look at
`org-colview.el' suggests that there are quite a few layers of
abstraction, so it doesn't look like a 10-minute hack...)

TIA,

-- 
Marcin Borkowski
http://mbork.pl