The issue of resolution is certainly an issue, and while it seems that you can do it in Construct, exactly what the best way to go about this is seems fairly unclear. I've started another thread in the support forum about this issue (before I found this topic, my bad), and there seems to be a few potential workarounds to it, but no definative solution.
Also are the DisplayWidth/Height expressions supposed to return the resolution of the monitor, rather than the game window, because I find it gives me the window size, which is the same as using the ScrollXRight or ScrollYBottom expressions. If this is what it is supposed to do, then a new expression that finds the actual width and height of the monitors resolution would certainly make scaling much easier.
I also like the two factions that seem to have sprung up, regarding high-res/low-res artwork for games. One group advocates the use of tiny windows and retro graphics to enable gameplay for as many people as possible, while the other group wants massive high-definition artwork on mega widescreen displays. I think both styles have their place, and some suit certain types of games better than others. For my current project though, I'm all up for lovely HD graphics at big sexy resolutions. And widescreen support is a must. I HATE it when games are made 4:3 only and look all stretched and crappy on my nice monitor. Support for ALL resolutions is greatly needed!