The SEB has revised the Nationals Supplementary Regulations to allow STR to be a National class and eligible for a National Championship this year if they have at least 51 drivers.
Quoted from the supps---
M.2. Street Touring R will be a National Championship class for the 2011 National Championship if the total number of participants
competing in Open and Ladies Classes combined is 51 or greater.
M.6. STR and STRL will run as supplemental classes providing Item #2 does not occur.
Full supps are here.
http://www.scca.com/documents/Solo_Forms/2011%20logoed%20Natl%20Supps%206.23.pdf