We have been working on evaluating and designing mechanisms that will reduce TCP's reliance on the retransmission timer for repairing segment loss, as well as correcting the RTO estimate when it fails. A few references:

Papers

Josh Blanton, Ethan Blanton, Mark Allman. Using Spurious Retransmissions to Adapt the Retransmission Timeout. Technical Report 08-005, International Computer Science Institute, August 2008.
Mark Allman, Konstantin Avrachenkov, Urtzi Ayesta, Josh Blanton, Per Hurtig. Early Retransmit for TCP and SCTP, August 2008. Internet-Draft draft-ietf-tcpm-early-rexmt-00.txt (work in progress).
- Status report presented at IETF 69, July 2007.
- Status report presented at IETF 56, March 2003.
Mark Allman, Hari Balakrishnan, Sally Floyd. Enhancing TCP's Loss Recovery Using Limited Transmit, January 2001. RFC 3042.

Talks

Josh Blanton. Comparing RTO Reduction Algorithms in TCP, NASA Glenn Research Center, August 2003. Slides.

(Posted: Mon Feb 24, 2003; Updated: Wed Oct 1, 2008)