I had an idea like this...
Except that I didn't want to use tons of locations.
So I designed a system whereby the player has a corsair, and disruption webs at the time and place that he wants an explosion, after selecting the frequency/type of explosion.
Then the disruption web was removed and replaced with a burrowed ling. The lings continuously changed ownership through the different players, and every time it got to the right player, an explosion would occur there (center location + explosion).
This way, I used just 1 location, and minimal triggers.
But then I found a problem with giving burrowed units to different players, and I couldn't find a way to stop the lings from unburrowing. I should do some more testing (I have looked at
this tute).
Anyway, I think that it's a pretty cool idea.