As noted above, the K9YC vertical dipole is a good simple example of using the coax shield as part of the antenna.
There are more examples I can share:
End Connected Off Center Fed Dipole - An alternate OCFD design.
Gain Master Antenna Model - Center fed 5/8 wavelength vertical dipole makes use of the coax shield for the lower leg. I created an EZNEC model of it in order to understand how it worked, and how it was matched to 50 ohms which is explained.
The End Fed Half Wave (EFHW) design using the 49:1 transformer makes use of the coax shield as a counterpoise for the return currents, most designs don't show it, but a common mode choke should be placed about 0.05 wavelength (on the lowest band) down the coax.
Getting off topic, but relevant:
Anywhere someone is using an unun (unbalanced to unbalanced) transformer - the ground lug is common to the coax shield, often without realizing it the coax shield is part of the antenna system. Others realize this and place a common mode choke at the appropriate point depending on the design - often to get multi band operation with an ATU (and accepting SWR related coax losses). Take a look at Balun Designs ununs where they show pictures of the inside.
The private life of coax will further show how any imbalance results in current "spilling over" and flowing on the coax shield if its not properly choked.