I have made a Czech Pilsner using S-23 Yeast and had very good results fermenting in a small refrigerator. Since, I don't have that refrigerator any longer, is there a substitute yeast that doesn't require as low a temperature as S-23 while giving similar results? A yeast in the low 64F/17C would be ideal. I believe a substitute yeast would be a compromise, but I'm looking for options, as I really like this style. Thanks.
Lager yeasts generally need lower temperatures. They will also ferment at higher temperatures (they don't die), but the resulting beer may have serious off-flavors. I doubt that you'll get terrible off-flavors at 17C already, though.
In your case, where you only have to cover ~10C, I'd look into alternative methods of temperature control, for example, moving the fermenter to a basement (if you have one), putting the fermenter in a tub of cold water, or putting wet towels on / around the fermenter.
A quick web search will come up with other ideas for cooling, including some hardware that isn't as expensive as a fridge.