Have you built RPMs from their source SRPMs before? I'd suggest getting one of the SRPMs from SCL and building it on the Pi. You'll probably have to incrementally build the whole tool chain, just as those in scl were built. It's possible you could get the person who built the scl versions for x86_64 to add armv7hl to their list of build architectures and it would build and appear automatically. (I'm not familiar enough with the process to know just how automated that is.)