For systems that arn't running a Dark Ages version of SunOS (Read Solaris) you can set the queue length on a live system with the command:
/usr/sbin/ndd -set /dev/tcp tcp_conn_req_max <NUM>Solaris 2 -> 2.4 max is really 32, 2.5, 2.5.1 2.6 etc its 1024 and 7 8 9(SunOS 5.7, 5.8 and 5.9) it is 2048.

If you are Running a version of SunOS you still need to recompile the Kernel (Read SunOS 4.1.3u or earlier) to make these changes you should think about just hiring some monkey to shout ones and zeros at the ethernet port.

-Waswas