[Android Software/Hacking General [Developers Only]] meltwater:
This is an interesting question!

Although my tablet is WVGA which is the same as the blackstone (so I can't test this directly!).

You'd need a much higher resolution device to go beyond the officially supported resolutions, (obviously Android 3.0 supports more).

From what I've read and from doing some app development, apps should scale to fit the screen (if programmed correctly). I've read that some apps don't scale for some tablets, what the root reason is for this, I wouldn't know, since the support is there in the API.

Basically, the android sdk provides various ways to describe the layout of your screens, and they encourage you to use ones which describe them in terms of proportional amounts (for the Linear Layout) or in terms of position of items i.e. to the left of item A (for Relative Layout) etc. The other layouts all work along the same lines, i.e. you don't worry about the size of the screen and calculate each position by hand like you do with windows mobile etc, it is all determined by the API.

You can see the different layouts code here and if you find the ApiDemo APK (I'll post if you like) you can view them. However, you can break all the rules and still use the Absolute Layout, where you return to the good old days of x,y co-ordinates. Even then you can use a values which are relative to the screen size and pixel pitch (see Difference of px, dp, dip and sp in android..) so there really is no reason to hard-code it.

As for graphics, I've not done this yet, but I know this handled if you use "9-patch" png files...they describe them here.

View attachment 566688

The idea here is that the black pixels around the edge allow the designer to say which bits are fixed size and which bits can be stretched to fit etc. It is a really tidy way to do it I think. Imagine how you'd have to do it otherwise if you created a button image with an icon on which would need to be resized to fit!

Oh, there are also provisions to provide low-res, med-res and high-res versions of the graphical resources, so again everything should scale nicely and look good without the need to scale everything all the time. There shouldn't be any need as such for "large" versions of apps, unless the developer wants to change how the app works by making use of the extra space or if they want ensure the "small" version takes up less space. I'm not sure how it determines which resource to use etc or if they all get installed etc, I've not looked into it.

So as long as the designer of the app has done all this correctly then it "should" scale correctly to whatever resolution. Of course, to claim this is true, they would need to test all resolutions. Fortunately you can manually create high-resolution emulated devices so it can be done but that is not the default.

[Now you mention it though, I shall ensure I test any apps I create at least once in high-resolution, it sounds like a good idea!]

I think this might have been why the retina display didn't make it to the iPad2, it would have required app developers to produce yet more app versions to deal with it and re-do the graphics yet again. Unfortunately I don't know anything about how iOS deals with these things, but you don't get the standard sized app in the middle of the screen or a x2 type option as you do with iPads.

Thanks for posting the question, hopefully it answers it (in theory anyway).