Hi there! As I was searching for more AR, I came across a Doraemon episode featuring just that. Specifically, episode 734 of the current anime, called in Japanese "ママ、小学生になる", or "Mama became an elementary school student"; the _title_ is pretty much self-explanatory.
Long story short, as Doraemon was doing laundry, the Time Cloth is blown off by the wind and ends up wrapping around Nobita's mom, regressing her into a child. She takes advantage of the situation to pass herself off as another student and find out what secret he's been hiding from her. It's really cute and the AR, although partially hidden by the cloth, has decent process. It leaves her in baggy clothes, but she just fixes the problem by tying a knot so they don't bother her.
As a side note, I'm really glad I came across that; I've always found Nobita's mom to be surprisingly cute, and I'm really glad to FINALLY see an episode that features her getting ARed (It certainly took them long enough, but better late than never). Now if only they could do an AR of Shizuka!
I apologize for the video's lousy visual quality, finding "current" Doraemon episodes in good quality is surprisingly hard.https://www.youtube.com/watch?v=7WDXiX_fVII
EDIT: Oops, forgot the timestamps: the episode starts at 10:03, and the AR at 11:06.