[snipped lots of good stuff]
> Viscounts (vicomte) are vice-counts, and are inferior to counts. To my
> knowledge this rank does not exist in German. My Langenscheidt identifies
> viscount as an English title with no translation. If this is incorrect I
> would be very interested in the name for this title.

There's no equivalent that I know of. Later the title of Freiherr
(equivalent to baron) was created.
The German system was not as well structured as the English system.
In fact, it was quite confusing. Yesterday I talked to a friend of
mine who is a student of history and we looked it up.

As you already stated, Graf (count from latin comes = companion)
first was an administrative title.
A Mark (march) was a tract of land that was recently conquered, and a
vassal with more military rights than a count was needed. Enter the
Markgraf (viscount). A viscount had the right of the Heerbann (call
to arms). In terms of power and social rank a Markgraf was equivalent
to a duke.
A Herzog (from Old High German herizogo, which designated a
military leader, English duke, from latin dux = leader) originally
was a tribe's elected military leader. Later this changed into a
hereditary noble title.
A Baron (baron) was the lowest ranking member of the Hochadel (high
nobility).
The Pfalzgraf has something of a special status. A Pfalz was one of
the Karolingian castles. The regent had no real capital, but
travelled across the land from on Pfalz to the next. Pfalzgraf was an
administrative title. I know of only one "domain" that later on used
that title, the "Pfalzgraf bei Rhein" (count palatine on the Rhine),
a very influential person on par with a duke or marquis, and later
one of the electors.
Fuerst is a term used to describe a member of the nobility and is a
superconcept for all the above.

So far, so good, but now things really get confusing.

Herzog, Markgraf, Pfalzgraf and Baron all belonged to the
Reichfuersten. This means, they swore fealty directly to the crown.
Some counts belonged in there as well, but most of the counts swore
fealty to a Markgraf or Herzog. This lead to the fractioning of the
empire and sometimes conflicting loyalties, since their highest
liegelord nominally still was the king, but their direct liegelord
was somebody else.

Later, Baron, Freiherr and Fuerst became mere titles, not necessarily
acompanied by land.

Sorry for using this much German on the list, but some of the phrases
really don't translate well into Englisch

laters

Kai