OK,so +-2V is a little change considering the nominal of 48V,you can just design for 50V output voltage and max current and just later slap on the variable part of the output voltage control.(If you make a reasonable design for 50V out,it will be reasonable for 46V also).
The CC part,think twice if you need
current limited or
constant current output.Also what should be the behaviour of the device when it hits the current limit/constant current threshold.Should it latch off,hiccup,foldback or lower the voltage to maintain the output current(constant current)
Another point to consider-Whatever your current sensing method it is it should obviously support currents in the ampere range,which means it will not measure at all or measure with highly degraded accuracy currents in the mA and below range.
Roughly the way I would go if I am given these specs is:
1)Design a normal boost that supports 50V @max long-term current output and minimum input voltage.
2)Add a DAC and whatever circuitry around it is required at the feedback point to change the output voltage.
3)Decide on the behaviour of the converter when subjected to overcurrent at the output.
4)Modify the circuit to get the desired behaviour when subjected to overcurrent when being careful to not push the converter outside it's comfort zone(too low/high duty cycle for example is a problem).
This approach will give you alot of knowledge and experience,but might be too much for someone who doesn't have much experience and will consume alot of development time.
The other option I see as viable is too find all converters that are I2C/SPI controlled(that would filter a significant part of them) then filter them by supported input/output voltages(in the voltage ranges you are looking for there are alot of LED backlight driver chips,but they aren't generally suitable for something other than....led driving)
If you find something that fits you perfectly great-(I don't think there is a perfect fit for that kind of requirements as in a single chip solution)
Otherwise you would either have to compromise on some aspects of your requirements or take the first approach.
As for the LM5122-as many other converter chips it seems controlled by analogue means,so you will have to use DACs and Digipots.
Got a little carried away
