Ive seen it done on two different occasions and it looked very good and very similiar to the coco fiber, I dont see why a brom or epi wouldnt root, Ive seen plants that arent considered epis and are definatly not broms root on barely nothing! even rocks! if I find the pics of the terrarium Ill post them for you =)

To chime in on this one, as well, it depends on how long you want your setup to last. I'm not sure what the lifespan of coco fiber is.
I used NZ spag, in mine, instead of the coco fiber and it's worked out ok.
I will say that I wouldn't use it again. It wasn't a disaster, but it all started to fall off after a year or so!
Fortunately, I had really just used it to cover a few areas that were covered by mosses later.
I used the silicone to attach it to the foam areas that were bare. I do think that you could get better results by having large pieces of the appropriate wood as a cover.
The wood will look and work better in the longterm. (I personally think!)
Also, try using large, lightweight rock formations. (Well secured!!) Many things will grow well like that, if done right. Although I don't have Bromeliads, my orchids, ferns, mosses, etc, do very well.
You can rip it all out if it doesn't work down the road, but it's so much easier to take your time and plan for eventuallities from the start. ;~)
I haven't ever used it, but I've heard some really good things about Epiweb! I do think that I'll try it in my next project.
Scott