"sys.maxsize" won't work.  inspect.Signature parses the __text_signature__ using ast.parse, and it only recognizes constant values and named constants (True/False/None) for the default value for parameters.  Playing with ast, it looks like we'd have to support a tree of Attribute nodes, then look up sys (or whatever) and recursively getattr on it.  Which would be new code.

Anyway it seems like a bad idea:

    import inspect
    import re
    import sys

    sys.maxsize = 3
    inspect.signature(re.compile(".*").match)