Well I have other question. In my country we have newspaper about different shows, and they release it two times in month. And in two pages they wrote alphabet of CSI and in S - spin-off they wrote about spin-offs we know, but they wrote something like this: producers planned CSI: London and CSI: New Orleans, but they resign. My question is - have anyone find or heard something about this? CSI: London sounds intriguing. I write here cause I think it's good topic.
I'm sure they considered various options to expand the franchise when it was at the height of its popularity, so that could be a rumor, or it could be true. I can't remember reading about CSI: London or NO specifically, but I might have forgotten! It's been a long time, haha.
Oh, I just found this article from 2007 which mentioned plans to film in London, but I'm not sure if they were considering a backdoor pilot or just a one-off storyline there...
Judging by the date of that article, I'm guessing the Writer's Strike later that year halted any London spinoff. Also WP left CSI the following year.
Also IIRC, there was talk of William Petersen going to London for a CSI ep clear back in 2004 and 05. Possibly a pilot for a spinoff, I think. Anyway, it didn't happen because he was diagnosed with an irregular heartbeat at that time. That's why WP isn't in some episodes of season 5 much.