For most of the rest it's possible to start in C and link in the language runtime, it's much easier to start in the runtime and extend it with C modules. From experience this is especially true for Python: I've used both ctypes and SWIG to turn the guts of existing native programs into Python libraries. I'm sure it's probably the case for Ruby and Perl as well.
You could also just use Go by itself :)
As a bonus, the border between the two languages often settles along conceptual seams in the codebase -- your low-level graphics rendering code shouldn't be tangled up with your enemy AI or UI templates, for example.
Rather than writing everything in a language that tries to do everything and winds a mess (C++), you can use two smaller, more focused languages.
You would take your C+Python app and rewrite the C bits in C++ and find it shorter and clearer and the same speed.