I just saw an ad with extensions turned on which said:
Exclusive Deals on ... - Save on ... - Order Today!
Basically those are the three extensions with (probably) same links, and together they make a sentence which is all linked, just like if the text of an ad was a link.
I'm guessing this is not what AdWords developers have aimed ad extensions for - but maybe they did - this would be quite an extended ad.
I wonder what would AdWords folks say about it.