Right, sounds like your are trying to achieve what I am also trying to achieve, difference being, my flies need to be cast on a single handed rod rather than a salmon rod.
I have found there are two items out there that give me a bulky body (no, not steroids!) whilst retaining castability. The first is a kind of 1.5" straggle fritz thing that I do not know the name of just now (Yankie I think), but will get it for you. Angus Angling has it in loads of different colours. Its like the Veniard stuff, but the colours are better and it is more solid once tied in.
Once tied in and brushed back, you get a fly that is around 1.5" across that does not thin down in water. Add a bucktail collar every 3-4 turns and you have a very bulky fly around 6" long.
I tie another version of the above fly that uses EP Fibre as a wing, but it is tied in "wide" to shroud the body. This again keeps its shape in water.
Using EP brushes you get a very different look. It is not so sparkly for one, so if you want solid colour rather than flash, this is the one to go for. They do do a version with subtle sparkle, so you can ring the changes. The EP version is easy to trim with scissors two so you can taper the fly. You can also tie it onto an articulated shank, trim to shape and end up with a highly mobile fly that looks like and swims like a jointed Rapala. When using Ep I tend not to bother with a "wing", no need for it.
I will try and dig out some example flies.
