PVNet is a project providing a virtual network interface. It generates numbers of pure virtual ethernet adapter. It is tested for Linux kernel 3.0.8 on amd64 cpu. Its code contains a kernel patch and module code. You can use it to create many ethernet cards. Each device has a single mac address.
LiMon (Linux Monitor) is a free/open/libre multiplataform real time Linux monitor written in C/C++, and other languages. Monitor of server's relevant aspects, such as services, temperature, CPU, memory and disk usage, etc.