There are no official rpm's but you can head over to kernel.org and source compile a kernel just fine. I run quiet a few machines with RHEL3.x and 2.6.x kernels and have had no issues. Due note that the 2.6.12.x has trouble with hyperthreading so stick with 18.104.22.168 if you need hyperthreading enabled.
John W, CISSP, C|EH
MS Information Security and Assurance ITEagleEye.com - Server Administration and Security Yawig.com - Managed VPS and Dedicated Servers with VIP Service