[Bluecortina]

Do you happen to know the relative costs of a channel of the 5000?

I'm afraid the article I came across only lists the price in 1981. I'd assume the BBC along with NBC purchased the 5000. Wiki suggests there were two editions. Painbox and Edibox.

Not that it really matters, but the 5000/5001 (NTSC/PAL in that order) are live picture manipulators, ie they can flip/tumble/spin live pictures as per many LE shows of the 80's - think 'Top of the Pops' etc. The Paintbox can only generate graphics and pictures with limited manipulation of those elements. An Edit box, as the name implies can internally edit pictures and graphics together etc. So these are 3 different types of kit rather than a variation on a single theme. But as I say this is not at all important after all this time so no need for either of us to be concerned any further - all ancient history!