I got my start in genomics working on an open source DNA sequencer. In the end, we built a powerful scanning fluorescent microscopy platform that saw a few beautiful experiments done on it. I always wondered when this might happen in a truly open way. With the right tech and a focused corporate backing it really could happen. Maybe this is the beginning of something very interesting.
Rather than sequencing, I think it would be better to develop a standardized platform for a wide range of microscopy, but nothing really ambitious. Each new feature you add increases the build challenge. For example, I've built a straightforward transmitted light microscope with automated XY stage and Z focus, with cheap electronics; changing from transmitted to fluorescence would require a great deal of additional components, complexity, and need for precision and accuracy in the design and the build. Adding a "growth chamber" around the scope would as well. Any sort of super-resolution, autofocus, extremely fine movements, etc, are pretty much off the table for a simple build.
Ideally you could draft off of the work done for openbuilds, which is mainly focused on printers, lasers, and CNC machines.
(there are several projects that attempt this; openflexure is an example, but every time I work with their design, I go back to leadscrews with NEMA steppers and linear rail.)
There's a lot more biology than just sequencing DNA. transmitted light microscopy of cells is remarkably useful if you can do it cheap.
