I found this polish by Nina Ultra Pro called Solar Flare at our local Sally's. And is it definitively a Not-So-Mellow Yellow! These pictures don't even begin to do justice to the NEON-ness of this polish! Think yellow highlighter. It's quite obnoxious. It never reached opaqueness, even after three coats. It dries really fast in a matte finish.
Then, just for fun, I added some Nina Ultra Pro Fuchsia Rage