Is Italian style gelato achievable with standard home ice cream makers and home freezers?
Since you say French-style ice cream works fine, but the gelato is freezing rock hard, I suspect the problem may simply be the serving temperature. Gelato needs to be served at a warmer temperature than ice cream. Unfortunately the temperatures I've found are pretty variable (some say 5F, some say 10-20F), but everyone consistently says gelato needs a higher temperature than ice cream.

So just try taking it out of the freezer 15 minutes before you want to serve.

If you don't want to do that, then actual gelato recipes probably won't work well, and you'll have to modify them. You can try some of the usual tricks for softening ice cream: add alcohol, sugar, fat, or additives like guar gum or xanthan gum. But keep in mind that they may cause you to stray a bit from the original gelato flavor or texture!