Wow, Matt, that must be close to a record: three uses of "polarized"
and they are all spelled differently (and all, um, 'non-standard').

A vertical slot antenna is horizontally polarized. A horizontal slot
antenna, while vertically polarized, emits in a standard dipole azimuth
pattern. You could try a pair of crossed horizontal slot antennas, fed
90 degrees out of phase, like the "turnstile" crossed dipole antenna.
(I don't see how you would actually do it, but you could try.) But why
bother, when it's easy to make an omnidirectional vertically polarized
antenna in other ways? I'm not saying there couldn't be reasons for
doing it, but please let us know what they are.

Cheers,
Tom