I'm about to shoot a short in San Francisco, and would like to shoot it on film...
I've been looking for someone in the city to sell me leftover stock
from a previous production, but I haven't found a taker.  I currently
have a DVX100A, and if I can't find an affordable solution, I will
fall back on video...

The short will be about 15 minutes, and I expect to shoot at least 80
minutes of footage.  I will also need to rent a camera.  How cheaply
can I do this in San Francisco?

What will be your release format? If it's likely to be released only
on the small screen, you could affordably shoot it on Super-8. Super-8
continues to be a popular format to assure the look of film, which can
be transfered to & edited on digital format to be released on VHS and
DVD.

My intention is to submit it to resfest 2006, which would be a larger
screen, although i'd be more than happy shooting on super 8. 
Honestly, i was hoping to get film stock scraps from previous
productions on the cheap, and mix formats.  so, to answer your
question, super 8 is fine... i just need to figure out the cheapest
possible way to shoot on film, including camera rental and telecining.

Wow - this is a loaded question!

80 minutes of footage translates to different amounts of
35mm, 16mm and 8mm stock. My guess is you're thinking
of shooting 16mm. Not super 16 - that's different too.
But, are you shooting B&W or color?
What film speed? How many fps are you shooting? 
Indoors? Outdoors?
Is this live action or for animaton?

Say you're shooting at 24 fps (not slow mo or fast mo),
16 mm, 80 minutes - you'll need about 2900 feet of film.
Film stock comes in 100ft and 400 ft mags. 
with 7 400ft mags and 1 100ft mag you get your 2900 feet of film

Kodak color negative film is about $142 for 400ft, $36 for 100ft.
www.kodak.com can give you all the details.
Short ends are kind of a thing of the past - most are 35mm anyway.
And the ones you'll find don't usually have matching emulsion #s.
Meaning there may be a variation in grain and color depending on
how old it is and how it was stored.

If you did get it straight from Kodak, you're talking approx. $1030
in film costs alone. That doesn't include the processing, prep for 
transfer, transfer and color correction. Those prices are determined
per foot of film.
If you're associated with an university, you may qualify
for a student discount but I think you're looking for something cheaper
and I don't know if you call this cheap.

Plus renting the camera. Ahhh, that's a tricky one.
Most rental houses want to know their camera is going into capable hands.
Do you have a DP picked out? What kind of camera? How many lenses?
Need a tripod? How many extra mags?
Rental is based on amount of days you want to rent. But what really
eats into your budget is the insurance you need to have in order to get
the camera. They want to know that if you drop the camera accidentally
into the bay, they will be able to replace that camera.
(They often want to know that you have location permits too!)

My reco - borrow one from a film school. Or buy one on e-bay, use it
and then re-sell it. A decent 16mm camera starts at $3000.
By buying your own camera, you don't have to worry about days of
rental and insurance - though you'll be taking all the risks.

If you decide to shoot on super 8 - then everything changes.

There are really no "short ends" of super 8.
the 50ft cartridges cost about $15 each - so you're talking around $900
but that's for color. B&W is a bit cheaper.

You can buy a camera on E-bay for real cheap - $30-50.
You'll still have the processing and transfer charges but they'll be
less per foot. (a good producer would know today's going rate)

Depending on where you shoot your film, you may need lighting
equipment - film lights burn brighter than your reg. light bulb.
If you don't use the right lights, your film may end up saturated with
the color of the light and not look normal. (For example, if I remember
correctly, a 60 watt bulb casts a red light on film.) and then there are
filters and gels. Renting those can be expensive too.

my reco is to contact a film place in your area like: http://www.sffs.org/
or contact a film school like: http://www.academyart.edu/
and tell them what you want to do. 
hook up with other aspiring filmmakers and work together to create a film.

otherwise, shoot it with your DV camera. It's a lot more forgiving than
film and a good way to learn.

hope this helps. - good luck.

first of all, chicago brain, thank you for the depth of your response.
 It was extremely illuminating, to say the least.

To answer some of your questions...

I was thinking of shooting on super 16 because of the larger aspect
ratio but, you're right, 16mm will probably be cheaper and easier to
manage.  I'm shooting in color but i was open to black in white if it
was cheaper.  The film speed will be 24fps, or maybe eve 23 or 22.  I
haven't decided on that yet.Outdorrs mostly, in the san francisco
winter (overcast).  This is for live action.

I'm sad to hear about the death of short ends.  I guess i was
daydreaming about coming across 35 for cheap and shooting something
that looked like wong kar wai's "happy together." I should stop
daydreaming.

I am not associated with a university.
I can deal with rental houses because i am associated with a film
production company who will let me use their name.
The dp is me. it's cheaper that way.
Location permits....yeesh.  no dice.

I'm open to super 8, but i'd rather have 16.  I have lighting
equipment, but a lot of the shooting has to take place outdoors,
unfortunatley.

I have already storyboarded, choreagraphed and roll called for the
short, so i really don't want to dilute the project with student
filmmakers.

Again, thank you so much for your response.  It has helped me organize
my thoughts quite a bit.