When I took out the old fixture, I neglected to note the configuration (small mistake, big headaches!). Unlike all other configs in the condo, this one has: on one side - black, red, white and ground; on the other side, black, white and ground. Both grounds are connected to the box. I've tried a zillion combinations but none of them work. Any hints out there?

Are there two switches, or more, that control this light?

There's only one - however, I've solved the problem: First, thanks to a comment I found on another site, I replaced my switch, which as suggested, I had blown during one of my tests. Second, I then went back to the basic solution recommended by several others - all white, all black + red together. Finally, I used only one black and white, instead of the two of each (which I think is what you were getting to). This did the trick.
Anyway, thanks for the response, TK - much appreciated.