You probably won't be able to run it outside of no$gba, as you don't have the private keys to sign a retail build.
Other than that, pretty sure that if you know where to look and how to scramble together a working TWLSDK with all the private parts at the right places, pretty sure enough parts have leaked to be actually possible to build a dev build.
Other than that, pretty sure that if you know where to look and how to scramble together a working TWLSDK with all the private parts at the right places, pretty sure enough parts have leaked to be actually possible to build a dev build.