We all know a link from a PR 10 site is considered a much more
powerful vote than a PR 1 site (page).  The question is: "how much
more."

I don't know if this exists, but I am trying to find a chart that
measures the relative strength of each incremental point on Google's
PageRank.

Hypothetical situation:

If Google's homepage (which has a PR 10) were linked to a page on my
site

AND

I was the only outbound link on that (Google's) page (i.e. I would not
split the vote with other sites),

THEN

How many different sites/pages with PR 1 pages (each with only one
outbound link to me) would have to link to me to give me the
equivalent vote of one PR 10 page vote?

Consider in both scenarios (PR 1 versus PR 10) that all things are
equal (i.e. only one outbound link to my site [hypothetical page])

I am not interested in speculation found on a bulletin board (see link
below), but some industry accepted measurement/metric (or opinion from
a reputatable/believable source).
 http://www.webmasterworld.com/forum3/2754.htm

The chart should look something like this (I'm making up the numbers),
where either PR 1 or PR 10 is the basis for the comparison.

PageRank=How Many PR 1 votes
10=1,000,000
9=500,000
8=100,000
7=50,000
6=25,000
5=5000
4=1000
3=100
2=10
1=1

I realize Google would never release this information, but I'm
wondering if some 'genius mathemetician' has ventured an educated
guess.

We can’t know the exact details of the scale because, as we’ll see
later, the maximum PR of all pages on the web changes every month when
Google does its re-indexing! If we presume the scale is logarithmic
(although there is only anecdotal evidence for this at the time of
writing) then Google could simply give the highest actual PR page a
toolbar PR of 10 and scale the rest appropriately.
http://www.iprcom.com/papers/pagerank/index.html

Links to white papers on this subject (all without a definitive
answer) are at:
http://www.marketzone.net/directory/default.asp?CategoryID=29

Page Rank is also not solely based on external links; relevent content
is also a high factor, as well as internal links, and links to the
outside. The thought that every PR1 page would raise X amount per PR10
page linking to it, is not a complete scope of understanding.

webadept-ga

Perhaps you'd enjoy a look at this page
which examines Google's PigeonRank™
page-ranking system:
http://catalogs.google.com/technology/pigeonrank.html

Check http://citeseer.nj.nec.com/page98pagerank.html