With PLT Spy - the Python implementation for the PLT Scheme runtime - development continues. The current approach is to bring the CPython API to PLT Spy and integrate it into the PLT Scheme runtime, making it possible to use CPython extensions. The goal is to be able to use almost all extensions and also the original C code for standard types in PLT Spy, thereby making all CPython libraries available at once.
That sounds very good, but it raises the question of why one should still use PLT Spy - the linked article provides some answers, but concrete details will only be apparent once things have progressed further.