Rubén Gómez of Bible Software Review (which is experiencing a resurgence) has blogged about the availability of grammatically tagged editions of uncial Greek manuscripts in Accordance. As Rubén points out, we now offer digital editions of the following codices: Vaticanus, Sinaiticus, Bezae, and Washingtonensis. Be sure to check out Rubén's discussion of these resources.
Creating a digital edition of a Greek manuscript (as opposed to showing scanned images of its pages) presents special challenges which had to be dealt with. For a discussion of the rationale behind Accordance's tagged uncial manuscripts, see this paper by the scholar who developed them.