You're right. I totally forgot that. But I have read space constraints is Nokia's reason they don't put the Xenon in the slider. And I've seen pictures of the capacitors next to the phones and they are pretty big. To be fair, the C905 is a much thicker phone overall than the N86, which is 16.5 mm. The C905 is 18 mm and widens out to 19.5 mm where the camera (flash and lens) are. The N82 for comparisons sake is 17.3 mm. So the N86 is thinner overall than the N82 and additionally loses space due to being a slider. Also on the C905 there is an obvious buldge to accomodate the camera mechanism.
So it does still seem that being a slider on top of being the thinnest phone of the lot, creates the size constraints that prohibit putting in the capacitor for a Xenon flash. So I guess the question is, do people want to give up the thinness or deal with a big buldge in one spot, in order to accomodate the Xenon flash. I bet that even if people in the forums here are fine with that, that for marketing purposes more people care about thinness than Xenon.
I think the issue with a 2.6" screen is the length, not the width. A longer screen would make it pretty cramped to get a D-pad and keypad and everything onto a candy bar style phone with the dimensions of the N82. The N82 is also 8-9 mm longer than the N86 and N85. Nokia seems to have a made a decision to try to make the phone smaller in all dimensions, rather than larger.
Let's be fair. You show a picture in a dark room with no flash and then with a Xenon flash. One picture is completely black, the other you can see a canister on a what I assume is a bed. But then you conclude that you couldn't due this with and LED flash, as if the black picture represents the results an LED flash would produce. Obviously you would see the cannister pretty clearly as well with the LED flash. So you really need three pictures, if you want to make a point about the LED flash.
Also, why would anyone want to take a picture in a dark room without any lights on? This is a totally fabricated situation. Even in a dark bar, as mentioned by someone in an earlier post, there are sources of light. It's not just a room with the lights completely out. So your example doesn't have much to do with real life situations. It's exaggerated to prove a point. Anyway, as someone else said, no one is arguing that the Xenon isn't good. There just saying there are a lot of benefits to be had from better sensors in low light conditions. This already exists in regular digitial cameras. So it's not unreasonable to expect it in camera phones. And the better the sensors, the less there are situations in which a flash is necessary. And that is good, as far as I'm concerned, because I think all photos that require flashes look really bad.