Here's a lower profile one, though lacking shielding:

Two turns #24 hookup wire, soldered to a length of RG-174. I forget if I put a termination resistor on it or not... (Huh, just checking, it measure 26 ohms at the connector end. Now I
really don't know what I did...

)
The effect of no shielding, is some E-field sensitivity. This can be somewhat inconvenient in practice, but when understood, can also be kind of useful.
It could also be made with a balun, turning the balanced loop into coax. This would perform about as well as the coax loop type above.
I've also tried the slotted cylinder shield; it has lower sensitivity, and an off-center axis (because the slot acts like an angled end). The coil inside is still a dipole, you literally just can't put anything on the other end of it, mechanically or electrically. I don't think this is all that helpful. I prefer the open loop style.
Tim