[cycomanic]

E-beam lithography is used for research purposes all the time, so yes it's already used for "dev-boards".

That said, apart from the economics (it is very slow), you are also constrained with respect to the size of what you can write, the writing fields is typically quite small, if you want to make a chip larger than that you need to stitch fields together and you have to deal with stitching errors (which becomes more and more difficult the smaller your structures are).