speakers in vents

[AC72]

I have an idea, probably been done, but here goes.........I was taking my vents off last night to paint them and thought, why not put speakers here? They would be small, but would be great for some small mid/tweet combo. `My a/c doesnot work, and prob. never will. there is no ducting goin to these small vents (and prob never will be!). So what do you guys think? Or do you have any details of ones that you've done? Ihave not put a stereo in my truck yet, and it won't be anything to show, but i want it to sound nice. plans for the truck are driver/worker, pass on to son in a few years.....Anyway, sorry to bable on, but i thought this would be cool, let me know, thanks, AC
ps it's a 72 c20 lwb \