In the European systems that I was involved with, the 'low pressure' fuel system was regulated by a Bosch reg that was about 1 - 1.2 bar.
Fuel was circulated at this pressure up to the VP44 inj pump and then back to the tank via a fairly basic fuel cooler (rather like the simpler oil and trans fluid coolers) which took a little energy out of the fuel.
That way, the fuel tank was used as a heat sink for the energy put in by the VP44.
The recirculation from the regulator also went back into the tank and was not put straight back to the pump inlet - again to use the tank and its contents as a heat sink.
Of course, the tank ultimately heats up as fuel is depleted, but piping the system up this way certainly delayed the rise of temperature at the VP44 injection pump to become OK for passenger vehicles. Heavy duty stuff might be another matter.
We also had a thermostatic valve (Bosch again) on the return from the VP44. This diverted fuel back into the VP44 inlet, via the fuel filter, until the fuel temp got up to about 25-30ºC. This heats the filter in cold conditions. Once the temp was reached the fuel went to the cooler, tank, etc.
The pump is certainly capable of very high pressures, it is the same basic roller cell design as found in all EKP3 Bosch pumps. In some versions it will easily produce up to 7 bar. This depends on the armature used and the internal pressure relief valve, which should really not be used as a pressure regulator as it is important to keep fuel flowing through the pump to cool and lubricate it.