The newly published "Medieval clothing and textiles 6" (ed. by Robin Netherton and Gale R. Owen-Crocke) has an article on Stitches, Sutures, and Seams: "Embroidered" Parchment Repairs in Medieval Manuscripts.
I just opened the package, so I've only taken a brief look at the article, but it looks really cool. Parchment repairs per se are not unusual, but these repairs, mostly found in Northern Italy, Switzerland and Alsace, are executed in colourful silks and various abstract patterns, for example a sawtooth pattern seems to be quite common.
There are both black-and-white and even coloured photos of the repairs mentioned. Some holes have really intriguing fillings in buttonhole (?) stitch and the Cretan stitch is also used for keeping edges of holes together. The maybe best thing is that in the end of the article there's a thorough table of manuscripts with embroidered repairs, including current location, origin and approximate date.
Those who don't do textiles may not have encountered this series before, but all parts consist of articles written by experts and researches on different textile crafts in medieval Europe. The articles are well referenced with footnotes, but mostly quite readable and this is a really good series to have if you do textile crafts. For example part six has besides the above article, also one on Latvian dress 7th to 13th century, one on tabletwoven bands with lettering, one on used clothing trade in London in late Middle Ages etc. All parts are still available, so you can get 6 first and then consider collecting the others... (Anybody in this neck of woods can borrow my copy and I'm not the only one here with this series in the bookshelf.)
I don't know if the book is available through the bookshops yet as the official publication date is April 15 - I got mine through an Amazon.co.uk preorder. Which was a stupid move, because I paid 36.70 pounds for my copy (book 30.78 + shipping 5.92) while Bookdepository has it for 29.79 euros, total (i.e. I lost about 10 euros on the deal).