Rick,

I have a third seat for a 2000 A6 that may be willing to sell.  I have
only used it once since I had the car because my kids are all grown up.
Kids do like it because they get to look out the back of the car..  I
live in southern Minnesota so if you purchase the car and are still
looking for one let me know.

Brian

My A6 has the factory-fitted third row bench seat.  It's generally
quite useful, though there are a few drawbacks:

1. The seat itself weighs a huge amount, and so is an effort to fit and
remove. It presumably will slightly affect acceleration, and cost more
through increased gas consumption.

2. The footwell under it means that only a "space saver" spare wheel
can be carried.

3. The safety aspects of the tiny amount of space between the
rearward-facing children in the bench seat and the speeding BMW X5
behind you (whose driver has failed to notice that you've stopped)
should not be ignored.

4. Finally, although my children (10 and 7) thoroughly enjoy the
occasional trip in the seats,  on a longer journey (>20 minutes, or so)
the lack of room to stretch their legs out becomes irksome. (And they,
like their father, are not very tall.)

(5. And /really/ finally - though this isn't strictly relevant, so the
more serious-minded should stop reading now - the children love waving
vigorously to drivers of following cars. Apparently, this is a game
called "Sweet or Sour". The poor saps who are following us are deemed
"sweet" if they wave back, "sour" if they don't. It's quite amusing to
watch even the best-natured, most child-loving of following drivers
begin to tire of the relentless smiling and returning of waves after
fifteen miles or so, and slow to a crawl, allowing other cars to
overtake them, just for some respite.)

Best wishes,

Peter