If you find something closer to what you are thinking of, share a link. Interesting problem!

AZ and Vegas are basically the same, AZ gets a tiny bit more rain but not much.  

You could move to NB, Canada!

We only need A/C a few weeks a year vs. months a year.

OK, J/K...not helpful, I know.  I've been to AZ, but not Vegas.  It's brutal hot there (at least to me), so I can somewhat relate.

I think we might be talking about different cars.  my system doesn't have an automatic mode nor do I have automatic electric windows.

the a/c system was recently serviced and is "working" but it just won't keep up with the heat in my area, hence I'm searching for something to augment it to help it keep up.

yeah, that was the wrong link...but you get the idea.  there are replica versions that are fully functional and I'm thinking about something like that.  but i'm also looking at the tiny 12-volt ones that don't have to work great, just add a little extra.

Don't waste your money. Spend it on getting your AC worki9ng properly. Check your owners comic book to see if you are setting it properly. 

In most cars, if you set any air flow to the windshield, commonly known as defrost, the internals set themselves to introduce outside air to dehumidify the interior air. (If it didn't work that way, the melting and evaporation of the fog/frost on the inside just humidifies the air adding moisture to the windshield.) Set the controls for "recirculate" and the air temperature control to the lowest without "automatic" mode. Set the fan speed on medium so the air going through the AC coil has a chance to cool down. 

The swam cooler you linked to is a non-functioning replica that is unpainted to boot. All it does is push air into the cabin through a partially open window. It may not even work with the somewhat automatic electric windows in your car. Even if it does, you'd have to remove it and store it every time you wanted to lock your car. About as useful as chrome spinning hub caps.

has anyone tried anything like this?  

Link to Swamp Cooler on Ebay

My JDM car has A/C that has been recharged and is fully functional, but its just so weak I'm afraid it won't do enough where I live in the hot desert of Las Vegas.

I'm interested in 12-volt or other options to augment my weak-sauce system but don't want to waste my $$ on gimmicky bullcrap, so feel free to send over what you have used that actually works.