There are plenty of digitised cahiers de doléances available online. If I may ask, what exactly is your interest in this? (Feel free to PM if you're not comfortable discussing it in public.) I mean this quite sincerely, but if you're a graduate student, then you should already be familiar with most of these details, if only through your supervisor.

I say this only for two substantial reasons. First, as you say, there were tens of thousands recorded, and it's wise to remember that these are local, and not national, documents; they were largely spread around France, and to my knowledge most remain in local archives. Do an online search and you'll come up with plenty of individual sets: http://www.archives-finistere.fr/medias/medias.aspx?INSTANCE=exploitation&PORTAL_ID=portal_model_instance__cg29_decouvrir_itineraires_cahiersdoleances.xml&SYNCMENU=cg29_decouverte_itineraire_cahier, http://archives.allier.fr/1277-le-cahier-de-doleances-de-cerilly.htm, http://archives.tarn.fr/index.php?id=1011, http://www.archivespasdecalais.fr/Archives-en-ligne/Cahiers-de-doleances, and so on (there are bound to be hundreds of these available to consult online); or else reproduced (and often translated for American undergraduates) on certain websites, e.g. https://history.hanover.edu/texts/cahier.html. So they're really not very hard to access, and I daresay a good majority have by now been digitised. The main problem is their geographical range.

Secondly, you should also be (made) aware that a lot of work has been put into the cahiers de doléances as historical documents. In fact, in the hundreds of works published since 1789 on the pre- and early Revolution, in the thousands published since then on the causes of the Revolution, in the tens of thousands written since then on the Revolution as a whole, you'll almost always find discussions of the cahiers. And as specific texts, too. When George Taylor wrote his famous 'Revolutionary and Nonrevolutionary Content' in 1972, his was far from the first to wield the cahiers as a keystone for revolutionary thought in early 1789; take Hyslop in 1934, not to mention the thousands of 19th century works or -- naturally -- those in French. Since then, hundreds of studies have emerged on the topic, culminating in what remains the most exhaustive tome on them, Markoff and Shapiro's 1998 Revolutionary Demands. At some 600-700 pages long, you'd be hard pressed to find another as equally extensive.

Possibly you know all this already, which I hope if this is intended for scholarly research; but in that case, you should be already familiar with what's been digitised and those that remain unscanned in local archives.