Somewhere buried in my files I have a study that somebody did way back when that analyzed the basic break down of stations per market and the general trends in commercial formats based on those numbers. To sum it up, it basically said that if you have 5 stations you'd have a AC, a country, a rock, a news/talk/info and a CHR.
I don't remember the exact breakdowns, but th e6th was maybe oldies, the 7th a fracturing of the AC, 8th a second talk (usually programmed as ''talk' versus the "News' station, etc...9th a second rocker, etc etc etc
Now the caveat is that not every market follows this, etc, but GENERALLY there are trends that can be spotted in what format holes there are in a market, etc...
Having said that, and realizing that I know jack about Spanish formats, I would think a straight talk station might have more mass appeal than sports. Given that Sports is usually the 3rd or 4th talk station in a given market, seems like a talk station appealing to the hispanics would be the place to start...