Okay, I read through your description, and it seems to me as though you are talking about technologies that already exist. First, your basic idea seems to be that of a 1-D scanner - a photomultiplier tube (detector/diode/whatever), but instead of scanning just across, you scan across (±x), down (±y), and then along the diagonals (+x/-y, -x/+y).
So, on the face of it, it seems like this can be accomplished (1) by dithering, or (2) by octagonal pixels (which I'm sure some lab is already experimenting with). Dithering - which they do sometimes do with HST - is where you take your image, and then you move the camera over
exactly the distance of 1/2 a pixel, and then take your image again. After lots of math, you can then pull out more information than you had originally. I think octagonal - or just smaller - pixels would be easier, though, and more practical.
Another technology that is in use that seems similar is the push-broom detector. This is in use on many spacecraft, such as the
HiRISE camera on the Mars Reconnaissance Orbiter (I highly recommend taking a look at some of their photos ... 25 cm/px on Mars). This has a linear array of pixels that then "sweeps over" the landscape. So you have a fixed width and then arbitrary length, which is why many photos from modern-day craft are very rectangular. While it's not arbitrary resolution along the width, it offers arbitrary resolution along the length, limited by spacecraft stability, brightness of the landscape and detector gain, read-out time, etc.
And, by using a linear array of pixels, the system is going to be many faster than a single pixel recorder - which is what you're talking about, from my reading. And, for consumer electronics, the time gained by having an array instead of a line of pixels is even faster. When you're talking about 1/1000-sec exposures, or even 1/30-sec, I don't see your system being fast enough and precise enough, especially when modern CCD and CMOS array detectors have so much many advances and improvements that can be made without trying to develop a completely new technology that - at least based on what I read - seems to (a) already kinda exist, and (b) be a step back to how things were done 40 years ago with single-pixel detectors that scanned the sky.