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>     Where might I buy surgical tubing, without going to a dive shop or 
>     ordering through a mail order dive store, and paying ridiculous 
>     prices? Would a pharmacy or medical supply store have any? Thanks.

A medical supply place should have it.

Something you might try:  Your friendly neighborhood backpacking place will
probably have shock cord.  I bought three feet for about 50 cents, and it
works pretty well.  Tie a slip knot in each end to make a loop, slip the
loops over the mouthpiece, tighten, et voila!  You'll have to experiment
with the length (location of the knots).

Something else to be aware of, by the way:  the second stage will be
hanging by the mouthpiece.  On a conventional second stage, this creates a
fairly long water column between the mouthpiece and the valve
actuator/diaphragm junction.  This can cause free-flows when you first get
in the water.

Explanation:  When you first get in the water, the exhaust valve and tee
submerge first, then the lower edge of the diaphragm, then the center of
the diaphragm where it makes contact with the valve actuator, then the
upper diaphragm, and FINALLY the mouthpiece opening.  Until the regulator
mouthpiece hits the water, the second stage is filled with air and vented
to the atmosphere, so by definition the internal pressure is local ambient
atmospheric pressure.  The diaphragm center, and the actuator, however, are
1" to 2" underwater, and thus are seeing local ambient atmospheric pressure
plus 1"-2" of water column.  If, as is common, the second stage is adjusted
to start delivering air ("crack") at 1" water column differential pressure,
the regulator will behave as advertised, the valve will open, and you have
a free-flow.

You can fix this by increasing the cracking vacuum setting, but you get a
regulator that is harder to breathe.  You can work around it by turning the
second stage upside down, so the exhaust valve is ABOVE the mouthpiece, and
make certain you always enter the water this way, then turning it back
rightside up after you are solidly submerged.  Or you can buy an adjustable
second stage and dial it all the way to hard-breathing.

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