IntraText Digital Library: a project to create a digital library with concordances, statistics, and other useful things,based around some XML structure, worked out in immense detail, so that you can do whatever you like to the texts.
Would be so much better, though, if you could use all the tools on an entire corpus, rather than a single text. Or at least, it’d save on the pile of ad hoc scripts I end up using to work out what’s happening with chunks of sanskrit.