nitro:We'd love to upgrade to Snow Leopard but to do this and still receive support from these companies we'd have to upgrade to Quark 8 and Adobe CS4 at the same time.
What do you mean by "the same time?" Do you mean you couldn't get Quark 8 or CS4 without getting both?
And if I understand what your trouble is, you have Quark 7 or earlier and CS3 or earlier and they don't run under Snow Leopard. Is that correct? If so, you are asking both companies to write patches for programs they don't sell any longer so they can be made compatible with an OS that didn't exist when those versions were being sold. Right?
If that's what you want, I hope you can get it. Personally, I have no idea how many man-hours it would take to create those patches, or how much it would cost, but I'd bet the number of people who would be willing to pay for that effort is pretty low.
You might also consider what your response would be if one of your clients called and said: "You remember that 64-page black and white job you did for us two years ago? We just got a new color printer, and we want you to redo it in color, but we don't want to pay for it."
But like I said, I hope you can get what you want. Or you could keep the OS you have that works with your software.