Think it would be possible to get Sierra/Vivendi to issue a patch?
Nope. Most publishers only pay developers to support a game for so long; I'm mean it would be nice if publishers/developers would support their games for newer hardware, but realistically speaking you can't expect them to support a game forever. Believe it or not Riddick is almost 3 years old now.
Beyond that, I think one can safely assume that the market size of people with 2560x1600 displays that can also run the game reasonably well at that resolution is tiny. The cost/benefit just doesn't work out.
It still sucks, there are plenty of 3-5 year old games that I wish were still supported myself, but I can't really blame the developers. I guess some of that comes from being a programmer and knowing what it's like to have to support old products.