In case people stumble on this later...
Yes, memcache works perfectly fine along side suphp.
suPHP does not work with APC or any of the opcode cache tools. Thouch cpanel and other tools can enable this setting, at the implementation level, they are incompatible concepts.
"127.0.0.1:11211 may not running or not responding." can be caused by memcache being down, the port being blocked, and loopback not being configured on the server.
netstat -tap will show if memcache is loaded.
ping 127.0.0.1 will tell you if the loop back is working
telnet 127.0.0.1 11211 will tell you if the port is blocked
And that's all I have to say about that.