Currently there is no reason to rant about python3 and ssl, as there is no real wrapper yet.

But, for python2.x we got m2crypto.

Using m2crypto with nonblocking sockets?

PyObject *ssl_connect(SSL *ssl) {
    PyObject *obj = NULL;
    int r, err;
 
    Py_BEGIN_ALLOW_THREADS
    r = SSL_connect(ssl);
    Py_END_ALLOW_THREADS
 
 
    switch (SSL_get_error(ssl, r)) {
        case SSL_ERROR_NONE:
        case SSL_ERROR_ZERO_RETURN:
            obj = PyInt_FromLong((long)1);
            break;
        case SSL_ERROR_WANT_WRITE:
        case SSL_ERROR_WANT_READ:
            obj = PyInt_FromLong((long)0);
            break;
        case SSL_ERROR_SSL:
            PyErr_SetString(_ssl_err, ERR_reason_error_string(ERR_get_error()));
            obj = NULL;
            break;
        case SSL_ERROR_SYSCALL:
            err = ERR_get_error();
            if (err)
                PyErr_SetString(_ssl_err, ERR_reason_error_string(err));
            else if (r == 0)
                PyErr_SetString(_ssl_err, "unexpected eof");
            else if (r == -1)
                PyErr_SetFromErrno(_ssl_err);
            obj = NULL;
            break;
    }
 
 
    return obj;
}

_ssl.i
Once this is done, and returns 1, you need a magic oracle to get an idea what happend, and what needs to be done, same problem for nonblocking reads and writes.
Unfortunately m2crypto does not ship with such magic oracle.