Good post. I'll be in the same boat. I think I have about 40 Irish diesels now and I can't really justify spending at a bare minimum upwards of 4k on sound for all of them, even though I think sound is just the business. I am thinking I will ultimately fit sound to at least one of each Class/Engine example and maybe leave it at that, but I am also interested in fitting sound to the odd EGV (using only marginally cheaper sound fx chips).
I'd rather spend the money on models themselves when they are available so a price conscious DCC alternative is always welcome. Having said that, if you have LPv5's available, then I guess they would be better employed in the A's with its more comprehensive lighting functions than in the baby GM's or 121's which have no cab lighting from the factory.