Since I do many partial boils on the stovetop, I've been washing and immediately re-using my yeast. I rack my beer off the cake, pour in one gallon of store-bought bottled water, stir it all up, put the lid back on, and wait about 40 minutes. Then I pour the liquid back into the 1-gallon container and put it into the fridge. Then, after I have cleaned the fermenter and added my fresh wort and the rest of the make-up water, I check the temperature to make sure that it is cool enough (it usually is nearly room temperature), then I decant the 1-gallon of yeast liquid as my final gallon of make-up.
It's easy as I don't really have to do much extra except decant the suspended yeast. The bottled water is sanitary and so there isn't much additional risk of contamination (if your original batch is contaminated then you're screwed no matter how you reuse the yeast). I'm sure I am still overpitching yeast a bit, but not so much as as reusing the entire cake. The ferments start within a few hours and finish nicely; vigorous, but no beer-canos. I generally brew lower gravity beers so if they finish a little drier than they should, that's a win in my book.
My cellar is getting a bit too warm for ales now and I don't bother with refrigerating, so I am going to bottle my last beers for the summer (5 gallons of Centennial Blonde and 5 gallons of Deception Stout), compost my yeast cakes and focus on my wines and mead until the fall. My beer pipeline is well established and I should be replete with beer well into fall, when I will be able to start brewing ales again. My stout should be fabulous in December.