We are running Splunk 4.1.4 and I have enabled sslv3 and that works fine, however I am unable to specify (and make work) strong ciphers.
We need to specifically disable DES-CBC-SHA
When running btool debug I see the ciphers being specified but I still can connect to the web interface.
The cipher suite that you have specified in server.conf is effective for the SSL/TLS of splunkd's management port (port 8089 by default).
UPDATE: although in 4.0 through 4.2.5 it is not possible to specify a cipher suite for Splunk Web (port 8000 by default), in Splunk 4.3 and beyond, web.conf does accept the cipherSuite setting; see this link for more information.