SNMP Simulator is a software that would act like a multitude of real physical devices from SNMP Manager's point of view. Simulator builds and uses a database of physical devices' SNMP footprints to respond like their real counterparts do.
Project moved to GitHub: https://github.com/etingof/snmpsim
CASIMIR is a web-based PHP/MySQL interface which controls over SSH-secured connexions qemu/kvm virtual machines dispatched over several physical servers. It also provides to administrators the ability to delegate control of these machines to other users.