Probably old news, but Muddy Paws Racing stepped up to hold a 24 hour race at 9 mile. Muddy Paws Racing is a Wisconsin event promotion group focused on “promoting dirt in the Midwest.” Info can be found at Wausau24.com
Looks like it's cheaper too:

Dates 12 Hr 24 Hr
April 2 - May 24 $60 $75
May 25 - June 24 $75 $95
June 25 - July 28 $85 $110
July 29 - July 30 $100 $125