[R] combining bar and column graphs?

[Me]

Hi, I'm hoping to find out whether R, or an R add-on, can generate a 
particular type of graph. And, more basically, whether such a type of 
graph even makes sense.

I'm looking for something resembling both a column chart and a bar 
chart, where the basic visual "unit" is a solid rectangle of color that 
can be extended either horizontally, vertically, or both. The data that 
needs to be graphed consists of the relative contributions of a number 
(6 or 8) of companies (entities, whatever) to a common fund, over the 
course of a number of years (say, 1990-2008).  I'm picturing years on 
the X-axis, and dollar amounts on the Y-axis (say, $0-$100,000).  From a 
"temporal" perspective, every year will have at least one contributor, 
starting with dollar zero, but some years will have multiple 
contributors.  From a "company" perspective, some companies will 
contribute, e.g., dollars $1,001-$5,000 for several years running, 
visually forming a horizontal "block" riding on top of whatever happens 
to be below.

So as a simple example, between the years 2000 and 2001, Company A might 
inhabit a solid block extending from dollar zero to dollar 1000, two 
years wide. In year 2000, Company B might contribute dollars 
$1,001-$2,000, while right next door in year 2001, a different Company C 
might contribute dollars $1,001-$10,000.

Is it possible to have this sort of horizontal/vertical chart generated 
automatically, or is this impossible? Do I need to generate a 
year-on-year column graph and manually elide the boundaries between 
companies' contributions in successive years, thus forming the 
horizontal "blocks" I have in mind manually?  Is there perhaps another 
software tool that would be good for this?

Thanks very much - this is a long question...