Earlier quoted context omitted.
> I love the idea of a paid working trial of some length How long of a trial are you thinking of? If it's a significant amount of time, I think this could be hard to do from the perspective of the candidate. If I'm currently employed, there's probably no way I'm going to quit my job for a month-long paid trial period somewhere else. If it didn't work out, I'd find myself without a job and would be forced to take a ho…
I've seen six months work - that's time enough to ramp up somewhat and deliver. In that regard, it's plenty of time to assess the traits that we're looking for in strong developers.
That is the usual practice in countries like France, where new hires are on a trial basis for a period of one to six months (all other things being equal, the trial period only means that both the employee and the employer may terminate the contract at the end of the period with minimal administrative fuss).