Cordless phone batteries can be stored for a long time because they are NiCad which can be stored in a somewhat discharged state and have the least self discharge out of all the rechargables.

Fitzoid, you wrote that NiMH must be carefully conditioned (fully discahrged and recharged), I'm assuming that was just a type and you meant NiCad becauee NiMH you don't want to fully discharge and recharge if you can help it, NiCad are the only batteries which should be conditioned this way. NiMH, LiON and such you should recharge when you use them and not let them get too low so as to not use up all the charge cycles or risk cell polarity reversal.

Even NiCad don't have a shelf life of forever, if you were going to buy one of these radios then at least pull it out and recharge it on a regular basis depending on the cell technology. I wonder if any are using a big (think 1F) capacitor, a tiny headphone radio could run a while from one of those.
I don't care for the idea of a hand cranked radio either, maybe because most of them just seem so cheaply made but it seems it would be much simpler to have the charger seperate from the radio and use a standard battery.