Never seen one I’d actually trust for the mic, but I’ve seen a lot of Lenovos that have sliding covers for the camera.

I’m a little reluctant to put an adhesive slider on my MacBook because it closes pretty tight and I’m afraid the extra thickness would create a pressure point and cause damage over time.

Ebooks.com has a ton of DRM-free ebooks. They have a whole DRM-free section, plus a search filter, and they clearly display all available formats before purchase. That’s my first stop for ebooks.