When I first read the projector idea in the previous post I was thinking that you could create a program that runs multiple videos. This is a pretty easy application to write. In windows, just embed some media player controls into a form and size / move them around till you like them. Not sure how well 30 or 50 would run .. maybe kinda choppy if at all. So if that is the case, one work around would be to create a single video that is "the quilt" that has all the sub videos running. Then it could take as long as needed to generate the output, but when running it would be just a single smooth video.
The nice part of this idea is you can test the concept to see how it looks before you do a physical build or even buying a projector .. just see how it looks on screen. If you can borrow a projector, you can proof of concept the idea at the next level, again with little to no investment.
You can also resize the videos to be all the same or different sizes to see what you like better without having to actually buy equipment.
If you like the results, then it would be very easy to control it real time from your PC in your completed project.
One potential issue I see is the space needed. So regardless of it being back or forward projected, you still need space from the projector to the target screen(s). If you can work through that limitation and make it something you can "fold up", the projector idea may be very cost effective and compact to carry (specially with mini projectors getting better). This method could also provide the most flexibility in that you can change your screen layout on the screen and the configuration of the quilt .. or other surfaces / shapes.
Another potential issue is pixel size. Projectors are usually for standing back and looking at. So attempting to create a bunch if tiny screens may result in what is commonly known in the business as "crappy videos".
If this idea seems viable to you then you could write the application, build the armature to hold the quilt and then shine the videos onto your quilt. Outline the video boxes and then sew on little white screens that could have fancy borders to add artistic effect, etc. Maybe even make some of them have effects like when your in a fun house.
Even if the projector idea does not pan out, you may still want to consider the PC simulation to play with ideas.