HI Laurence,
Thank you for your reply. Your answer in fact made me realise that sometime ago I wanted to post the same question and then I didn't because I thought of the same argument, ie. use NLTK or another NLP platform in the backend.
My main motivation to ask this question is that AntConc seems to have an easy(er) way to extract concordances and collocations, and show them to a front end, whereas a library could probably require more work to yield a similar result. Furthermore, since there is in fact something, using an older version of AntConc as a backend, there seems to be someone who has more or less done the same, in the past.
In any case, thank you for your answer and I might use a network share at the end, as you also suggested.
Best,
Yannis