There's a GMO chestnut awaiting FDA approval that, with some luck, will be wholly immune to the blight and could prove to be the comeback generations have been waiting for. Unfortunately, this requires a rather long, painful bureaucratic process.
There are also groups crossing American and Asian chestnuts and then back-crossing them. Some are just exposing the offspring, and I think another is testing for the right genes.
(On my phone, otherwise I'd find some links.)