Not really. TCL didn't allow you to use one interpreter over several threads four years ago, and iirc TCL still isn't thread safe in that regard.
Guile does this with bravura.
Guile does this with bravura.
This avoids the Global Interpreter Lock problem that plagues Python. How does Guile handle that?
If you don't cross the C barrier again from your scheme code you can even use something like guile-fibers for Concurrent ML-like parallelism.