How to place an item between table rows, centered on the page.

[Daniel Pittman <daniel@rimspace.net>]

I would like to typeset one of two things[1] between each row of a table:
* a partial width line
* a graphic

The effect I would like to achieve is to make a visual distinction
between the rows of the table without a full width table line (as
achieved by \HL &c.).

I would like to have this item centered against the page it is in, not
aligned with the table columns. I currently have a table defined as:

\definetabulate[steps][|p(.3\hsize)|p|]

The closest I have been able to get to my goal has been to place an
additional row in the table following each row of content, containing
the following:

\NC \NC \blackrule[width=.2\hsize,height=1pt,depth=0pt] \NC \NR

That places a rule of around the right size at around the right place.
It has the fairly major drawback, however, of placing a full line height
of blank space between the rows containing content.

This is less than totally desirable; I would much rather ~ half a line
height of blank space with a rule centered in it, but less than that if
I end up using the graphic.

In the long term I suspect that the graphic divider will be used,
providing a more ornate separation of the steps. As such I would be
interested in knowing how to achieve both items, not just one.

Regards,
        Daniel

Footnotes: 
[1]  Actually, I would like to try both and see which one works best.

-- 
...Two and two are four. Sometimes, Winston. Sometimes they are five.
Sometimes they are three. Sometimes they are all of them at once. You must try
harder. It is not easy to become sane.
        -- George Orwell, _1984_