It would be nice to see Bittern return once again to the 'Silver link' guise even if its for one or two years. It would certainly pair well with a rake of teak coaches and would look excellent on a Severn Valley or North Yorkshire Moors railway gala.I've tweaked "new build" (which contravenes OPs steer) to "conversions" (thus guaranteed to eat up massive funds!).
I foolishly missed Bittern's temporary guise as 2509 Silver Link (too busy doing various Rail Rovers at that time!), so - yes - I'd love to see an A4 back in that condition.
I have all four of Hornby's 80th anniversary "Silver" A4s but sadly I cannot jistify funds for their glorious Silver Jubilee carriages.
As for the Silver link coaches, perhaps not yet. However, I could imagine in a couple of years, some secondhand might turn up cheap or could be reduced in a model shop after years of not shifting due to how expensive they are.