Sending TLS messages with out encryption using openssl code
Yes, there are a number of TLS cipher suites that don't include any encryption.  These cipher suites are not normally used by OpenSSL, but they can be explicitly requested e.g. using the -cipher option to the OpenSSL tools.

Specifically, the suites offering no encryption and/or authetication are found under the NULL and aNULL cipher classes.  The openssl ciphers manual page describes them as:


  "eNULL, NULL:
  the "NULL" ciphers that is those offering no encryption. Because these offer no encryption at all and are a security risk they are disabled unless explicitly included.
  
  aNULL:
  the cipher suites offering no authentication. This is currently the anonymous DH algorithms. These cipher suites are vulnerable to a "man in the middle" attack and so their use is normally discouraged."


To get a list of the cipher suites included in the NULL class, run openssl ciphers -v NULL.  For me, the returned list looks like this:

ECDHE-RSA-NULL-SHA      SSLv3 Kx=ECDH     Au=RSA  Enc=None      Mac=SHA1
ECDHE-ECDSA-NULL-SHA    SSLv3 Kx=ECDH     Au=ECDSA Enc=None      Mac=SHA1
AECDH-NULL-SHA          SSLv3 Kx=ECDH     Au=None Enc=None      Mac=SHA1
ECDH-RSA-NULL-SHA       SSLv3 Kx=ECDH/RSA Au=ECDH Enc=None      Mac=SHA1
ECDH-ECDSA-NULL-SHA     SSLv3 Kx=ECDH/ECDSA Au=ECDH Enc=None      Mac=SHA1
NULL-SHA256             TLSv1.2 Kx=RSA      Au=RSA  Enc=None      Mac=SHA256
NULL-SHA                SSLv3 Kx=RSA      Au=RSA  Enc=None      Mac=SHA1
NULL-MD5                SSLv3 Kx=RSA      Au=RSA  Enc=None      Mac=MD5 


To see if a specific server lets you connect to it using one of these suites, run:

openssl s_client -connect host:port -cipher NULL

Of course, for most services, this should cause the cipher suite negotiation to fail, like this:

$ openssl s_client -connect www.google.com:443 -cipher NULL
CONNECTED(00000003)
3073382600:error:14077410:SSL routines:SSL23_GET_SERVER_HELLO:sslv3 alert
handshake failure:s23_clnt.c:724:
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no peer certificate available
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No client certificate CA names sent
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SSL handshake has read 7 bytes and written 139 bytes
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New, (NONE), Cipher is (NONE)
Secure Renegotiation IS NOT supported
Compression: NONE
Expansion: NONE
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