Hey guys. Me again, the satellite guy. I took the picture last year and am an industry insider.
I'm pretty sure I can get the same IKONOS instrument again this year at no cost to y'all. I'll keep you up to date. I know DigitalGlobe has higher resolution, and if you want to follow that route as well, that's totally cool. There are pro's and con's and I'd love to drink a lot of beer with everyone and explain the inner workings of the instruments, since it's not necessarily a gimme that pixel resolution is the only differentiator. Not sure if they will both be available on the same day, but it might be good to get both arranged and try and have a piece that will last a few days. This will also reduce risk from dust storms or clouds (probably not a problem, but worth mentioning).
A few thing that will probably NOT make much difference except to make things a little blurrier than intended, because I think you're on a fine path....
Remember that the satellite pixels and the ground pixels will NOT line up unless The Man can exert some massive karma in to the heavens. As you work on your designs, you may want to try the following photoshop tests. Give yourself a bit of a boarder on the picture, upsample each pixel to 4x4, then offset the photo by cropping out a couple rows of pixels, then downsample back from 4x4 to 1x1 and be sure to use bilinear interpolation sampling, and not nearest neighbor.
Also remember that the panchromatic sensor is high resolution 1x1 and the color sensors are 4x4. In post processing, some wizardry is done to make it almost look like the image is color at 1x1. In order to not totally fuck up, I recommend keeping your detail lines a minimum of 2m pixels each for a line, and definitely much bigger than that for anything you NEED to see, and color is really going to need to be for fill, not lines.
Keep these in mind, and I'm sure things will work out.
One other thing, should you need to downscale, or if anyone else is considering doing a side-project. Emoticons are another thing that might work. They are instantly recognizable, small, and artists have done a lot to convey a big message in a small amount of pixel space. If you consider the design philosophy of art where every pixel counts, you're more likely to maximize your art without having to scale everything up.