LLVM 1.5 released with tail call optimization

From the release notes (http://llvm.cs.uiuc.edu/releases/1.5/docs/ReleaseNotes.html):

The release now includes support for proper tail calls, as required to implement languages like Scheme... In LLVM 1.5, the X86 code generator is the only target that has been enhanced to support proper tail calls (other targets will be enhanced in future). Further, because this support was added very close to the release, it is disabled by default. Pass -enable-x86-fastcc to llc to enable it (this will be enabled by default in the next release).

Is it time to create a PLT front-end for LLVM?