This pedal update has an interesting twist – the site Runoff Groove has taken several classic tube circuits and adapted them as pedals using MOSFETs. MOSFETs actually behave in a very triode-like manner.
They’ve taken the Matchless DC/30 design and adapted it as the Matchbox, the Dumble Overdrive circuit as the Umble, and the Boogie Mark I as the Uno. In fact, there are even more – check out their articles page.
These look pretty interesting, and I’ll probably build one, or even all three, of them at some point.
Ted Woods also tipped me off to another tube pedal, the Stephenson Amps Stage Hog, which uses a 12AX7 and a 12AU7 and can be operated as a tube distortion pedal or a practice amp.