I really need to go to bed, but I can't resist staying up and replying
on this subject!  I acquired a Melville Clark Apollo expression piano
about 6 years ago and it's been great.  The expression system does quite
well, and of course it's a foot pumper which is what I wanted most.  Mine
also has the original electric steamboat pump, but mine has an air motor
rather than the spring motor which seems to be more common.  My friend
Jere DeBacker (Boulder, Colorado) has rebuilt a number of these and
swears every single one is different from all others in some way.
Cynthia Craig (St. Louis) has one that has the full expression system
and spring-wind motor, but no original electric motor!  It's strange
that they would have installed everything to express automatically but
leave out the motor - it wasn't removed, it was like that originally.  I
love to study Melville Clark because he was such an important pioneer
and he had any important innovations, not to mention the QRS and Clark
roll companies which grew out of the Melville Clark Piano Company.  I
hope someday his full story is given the attention it deserves.

I recut about a dozen good expression rolls (QRS Automatic / Clark "red
X" / Seeburg XP) rolls for this system under my BluesTone label, mostly
longer rolls and mostly lively popular stuff (Wendling, Kortlander,
Confrey, Charley Straight, etc.) along with a rag medley - most are
still available.  I'm trying to get everything together for a web page
which will cover this and other recuts I have available, but I have to
do this in my spare time which is almost non-existent.

Tom, you mentioned "... I guess it uses Apollo X - Art Apollo - QRS
Autograph Automatic - or Price and Teeple Art Symphonola Roll(s)".  I'd
say you're right.  However I've never seen a Price & Teeple roll, much
less confirmed it's the same expression system as this, and I'm
skeptical.  It seems to me I asked Art Reblitz about it, since it's
mentioned in his Treasures book, and I believe he said he got the info.
second-hand and wasn't certain of its accuracy either.  Anyway, I've
been buying these roll types over the past 6 years whenever I get the
chance.  I find the rolls tend to be 1 of 3 types: (1) good pop rolls
along the lines of what I described above; (2) good classical rolls, all
taken from the QRS Autograph roll library (these include good stuff
played by Rudolph Ganz, Harold Bauer, Godowsky, etc.); and (3) dull
salon stuff a la Lee S. Roberts - unfortunately this 3rd category seems
to be the majority of the rolls you'll find, and if you're like me
you'll play them once (at most) and never again.  Another interesting
fact about these expression rolls is they're all on excellent paper and
usually turn up in very good condition.  Of course the salon stuff is
always in mint condition, since it probably was never played to begin
with.   ;-)

I'll let you know when my site is up.  If you want a list of the recuts
in the mean time please let me know and I'll be happy to send it
privately.  I hope you get your piano playing soon, if it isn't
already.  As you said, they're excellent pianos and both the foot pumping
and the good expression rolls are a lot of fun.  Also remember that if
you're a member of AMICA, our fearless editor Robin Pratt located an
original repairing / adjusting / regulating manual for this system and
reprinted it with the AMICA bulletin in 1995.  If you're not a member,
join and I'll twist Robin's arm into sending you a copy!

BTW, as of about 6 weeks ago my email address to rdeland@owc.net.

Cheers,
Rob DeLand
(dba BluesTone Music Rolls and trying to keep up with my grade school
kids)