It certainly was
At least if the nvidia_suspend() you mentioned is in the nvidia_subr.c file.
I changed ACPI to acpi and the system suspends ( I manually switched to a vt before trying ). My system actually came back up, and seemed to be usable ( could issue ping from a vt console ). There seemed to be one other issue ( firewire-related ), so not your problem
All in all: Thank you very much! Hope the ACPI->acpi gets included in future releases of the driver