Lately I've been using a "Serpentine belt tool set" used for compressing the spring loaded pulleys on a car so the serpentine belts can be changed.

Comes with a set of crowfoot wrenches (the 15mm is used on pedals), and a long flat handle that's almost 23" long. Fits on the flats on most pedals and has a longer handle (and more mechanical advantage) than any pedal wrench. They are often on sale at Harbor Freight for $12-$13, and the bonus is that you can use it to change the belts on your car too.

Position the crankarm to the bike's rear of the crank center, place a 9" cinderblock under the crankarm, and place a piece of a 2 X 4 on top of the cinder block (this setup prevents torque from being applied to the crankshaft). Place the crowfoot wrench on the pedal flat, and wrench away.

No stuck crank has resisted this setup yet.