First of all, the 93-96 Fleetwood Broughams are a completely different body style, so they play no part in your problem. The body style you have is from 1980 to 1992, and the Deville stopped in 1984. To go bare-top on your Brougham you will, at minimum, need the outside bare-top trim from an '80-'84 Deville (I don't know if coupes will work either). But, you will have the still have the enclosed rear glass, because the interior trim is bigger, and I think the formal rear glass (what you have) is covered, so trim replacement may not be enough. Basically you have three options:
1) It will look funny on the outside since the glass have a black ring around it, but get some Deville trim, and put it around your Brougham's rear glass.
2) This will be fine if the Brougham glass is not darkened around the edges. Get the Deville outside trim, and inside trim. Then put them in place around your Brougham rear glass.
3) This is the most sure fire way. Get both sets of trim and the Deville rear glass. Make sure you get one with the defogger if you wan to retain that option, since Devilles did not have it standard. I don't know if the plugs will hook up, but it shouldn't be too hard.
Note everything I just said is relative to the rear glass. There may be other bodywork/painting involved. And I have seen some attempts to remove a vinyl top that look pretty crappy, because they just gave up. For a fact you will have to deal with the B-pillar opera lights. B-pillar lights were only came on vinyl-top Broughams, so you won't be able to find any Deville parts to help you out. You'll probably just have to remove the trim and lights altogether, then do some body and paint work. You could get some old bare-top opera lights (from the C-pillar of Devilles) and put them there, put I don't know how they'd look. Personally, I'd just pay 300 bucks to get the top redone as opposed to all this replacement trim and body work. But hey..
Good luck!

Greg