The closest thing that I own to a .22 Pocket Pistol is my Walther PPK/S .22, which will certainly fit into a pocket, but isn't nearly as small as most would consider a Pocket Pistol nowadays.
However, I have repeatedly found myself eyeballing the North American Arms Sidewinder in .22WMR and I would love to own a Walther TPH in .22LR if I could ever find one fkr a good price.