Any chance of magic here? The printer is the only thing keeping me from switching, and it's a deal breaker. Here is the Brother download site:
Second, Solus does support the RPM package manager, although it's not recommended for most cases. If support for that printer really is a dealbreaker, you can install rpm from the software center, and use the automatic driver installer that Brother provides to install the drivers via rpm instead of eopkg. I do it for one of my machines.