Given the underwhelming reception to other American racing series' by the greater slot community, don't hold your breath, especially in the current economic condition.
The Racer/Sideways Daytona Protoypes are some of the best racing you can have at an affordable price & they have been universally bashed by the slot racing community. NASCAR is the most popular series on American TV & their cars continually undersell mfr's expectations. The SCX NASCARs are being blown out @ $20 & $25 on ebay & $30 by retailers. I don't even like NASCAR but I am getting 4 so I can set up an IROC series!
The IRL cars from Scalextric didn't sell well & as a sidenote the A1GP cars were even worse (I like them, & they're Dallaras!)
Many of us here in the States would love to see more DP's, liveries of GT's that are in ALMS, but we know its not likely.