As reported on BentRider Online, recumbent bikes dominated DFs at the recent 2007 running of the 24 Hours of Sebring.
"Leading the pack was Dennis Grelk in the Barracuda Streamliner with 522 miles completed in 24 hours. All of the major unfaired categories were won by Bacchetta Riders. John Schlitter had the fastest 24 hour run at 479.5 miles. James Kern led the 12 hour riders with 251.5 miles and Sarah Kay Carrel rode her Aero 367.6 miles to capture the women's 24 hour title."
In 2006 the top finishers in the 24 hour non-drafting event were:
516.5 miles - James Kern - recumbent
483.2 miles - Timothy Woudenberg - recumbent
474.9 miles - Doyce Johnson - recumbent
470.3 miles - Rick Rheingans - DF/upright
Here is a description of the races run at Sebring:
Bacchetta put this press release on their web pages after the 2006 event: