Thanks for the input, chaps, and I'm pleased to have sparked such an interesting debate.
I, too, think that BluRay is getting to the stage of being useful to small-volume producers (I reckon on 10 - 100 copies of my railway productions on DVD). Prices are a little higher this side of the pond, but computer BR drives are around £150 - 180, I saw TraxData (I think) write-once single-sided discs for about £2.50 each recently, and a HiFi mag had a review of BD players this month for £200 - £400. (They picked a Samsung at £200 and a Sony at £240 as best value.) At that price, I think it will begin to take off, though I don't think BR will ever reach as many homes as DVD.