Okay, forgetting some of the pros and cons, I've wondered how this would work in practical terms. Lets focus on what I know...the NICU.
To oversimplify, in the current system lets say there are 40 babies and 4 residents. Each resident covers 10 babies Mon-Friday, Various systems of cross-coverage usually have 2 or 3 residents rounding on Sat-Sunday. On call is q4 and the post-call resident leaves at noon or thereabouts the next day. I entirely realize this is an idealized scheme and isn't exactly what happens, but it isn't that far off and if properly handled, is consistent with residents basically following their own patients and working every 4th night and keeping in the 80 hours (if programs are good about not having early pre-rounds or keeping too late post-call, etc).
In a system maxing at 56 or 60 hours with let's say 12-16 hour maximums on a shift length, there are two possibilities I can readily see.
In one mode, you would basically go to pure shift work like in an ER. It wouldn't be easy to schedule this and crossover time would be needed, but basically 4 folks could cover 168 hours in a week and meet the rules with a 1-2 hour cross-over time at shift changes. Of course, in this scheme someone else is actually doing much of the daily care of the babies (rounds, physical exams, etc) - the resident can only be doing admissions and handling specific problems. Presumably the hospital has to either, 1) hire NNPs/PAs or hospitalists to see most patients, 2) Get attendings and fellows to do that (problematic as hour limitations may/will apply to them as well) or 3) Hire more residents who cover day-time which means, given RRC rules, a longer residency. This would not be easy, even with longer training you aren't all of a sudden going to have 4 more residents in that NICU as no one is going to double residency length for this. On the whole, I'd guess that academic children's hospitals would use a mixture of all 3 or these, mostly #1.
The second approach would be to use the residents to cover daytime only 7 days/week with some complex system by which the 4 residents would cover the daytimes and someone else would cover nights (same folks as in the first schema). This would give residents the longitudinal experience but not night-times. You could shift residents into some of the nights, but the 12-16 hour consecutive rule would make this very hard to schedule.
One could come up with a mix of these two such that on-service residents covered one night/week and some weekdays. You'd still need more residents or NNPs/PAs, but it would be feasible.
Bottom line would be increased costs, increased time of training, decreased role of residents in that NICU environment and the resident education being reduced (I think). Unlike an ER environment, shift work wouldn't allow for much teaching time as rounds would mostly go on without the resident as they'd be too busy handling problems or figuring out the patients.
I'd be interested in other ways people think this could be done in an ICU environment. I'm wondering if there are schemes that would be more effective for training. Has anyone plotted this out or the options and done a cost analysis for a pediatric setting?