Yeah, I think so too. There's so much out there about tarot and runes. But I haven't seen anything really good (from an historical or academic perspective) about the "simpler" forms of divination -- like the pendulum.
I suspect this is because the pendulum has been independently invented in just about every culture known to man... and because one's relationship with the pendulum's motivating spirit is personal. Most instructions for using the pendulum involve asking the device to show you how it will signal answers and the device demonstrating in response.
There doesn't seem to be a need for study or previous knowledge, unlike with tarot and runes, which have been used by thousands of people for hundreds of years, all working off more or less the same understanding of what each rune or card means, giving them substantial magical momentum and weight. It is counter-productive to try to re-invent the wheel when there is a magical interstate ready and waiting for you to get behind the wheel of your Porsche...
JMHO, YMMV of course.