Where can I find/buy an anologue cell phone (can't be digital or PCS)
with a RJ-11 connector that will work on the Bell Mobility Network in
Ontario.  I would prefer to deal with a Canadian supplier.  A used
phone would be fine.

Log onto PrairieMobile.com check out our Ontario location, try a
Motorola 3-watt bag phone with an S1936 Data-interface kit, bag phone
new probably ~~$300.00, S1936 ~~$279.00 Are you sending data or do you
need this for Fax's???

Data.

Contact Bell at Bell.ca find out about their CDPD coverage (Cellular
Digital Packet Data). A PCMCIA card and a laptop maybe what you
require. Bell's CDPD coverage in Ontario limited if not non-existant.
Western Canada actually has extensive coverage of CDPD. CDPD operates
at 19.2bps (MAX). If CDPD is not what you require a S1936/3-Watt bag
phone or even a Mobile Transciever (MT)can attain speeds of up to
14.4bps. Effectively a MT is a 3-watt bag phone and S-1936 built into
one ~~$500.00..  For $10.00 that's all you get.

is there a specific reason why digital cellphones cannot be linked to
a modem/fax by a RJ-11 connector and have to rely on PCMCIA cards,
etc.?

on a Nokia 5160 for example, the connector on the bottom allows to use
a headset - nothing more than an analog audio in/out actually.
wouldn't it be possible to use a modem/fax through this audio link on
the phone?

Actually there is a connector for the Nokia 6100 and 7100 series.
part# DLR-3P. Fax, File transfer, and internet access via serial
cable. this eliminates the need for a PCMCIA modem card. Compatable
with Windows 95,98,2000,NT and Workstation 4.0. The DLR-3P c/w config.
diskette and install guide.
I haven't sourced anything for the 5100 series. Good Luck!

I should add that all suppliers now make Data-Connectivity-Kits of
some sort. Not just Nokia. Some are more user friendly to install than
others ie. Motorola vs. Audiovox, but once you install the drivers
away you go! Data-Kits are carrier specific ( CDMA/TDMA/GSM ). A good
piece of advice is not to buy one at a mall Kiosk. Contact you
specific carrier and request a referal to a dealer.
Most networks offer a local dial-up number for your connection when
your traveling. Calling your carrier before you leave, my allievate
unnessary down time.

Buy any analog motorola flip phone and this:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=1352102926