This is just my thought but I don't think any hacking can make it or the picture look as good as a real glossy considering a glossy LCD is coated and that coating is what rocks.
However, there are some 'stick on' solutions that can give an impression of glossy but to me (I've seen it) it's not real glossy.
The reverse (on say the iMac) would kinda be pointless. You can remove the glass and put a 'stick on' solution but all your doing is pretty much blurring the glossy with a laminate and not accomplishing anything but ruining a nice computer display.
So as far as glossing up an ACD, you can try the 'stick on' solutions. They'll probably do the job (IMO not anywhere close) and it might accomplish what your wanting.