I never heard of a brand name or banjo maker called Alex - but I did find the name listed among Oriental Banjo makers at a website called Basic Bluegrass Banjo. There was no additional info about the name.

However, if you can know what makes a good guitar you can make a pretty good guess about what makes a good banjo; quality of workmanship, tuners, neck, string action and of course sound. Most good banjos have a bit of weight to them. I don't know if that's a rule, but it's something I've noticed.

I'd keep searching the banjo websites, search ebay of for anyone selling an Alex banjo, etc. Good Luck!