Just FYI, I routinely make static-ish builds. My mining distro is based on Debian, but the bitcoind binary on it is build on an ancient slackware box with wildly different libraries. Fudging the makefile for a static build gives me a binary that will run just about anywhere.
On the original topic, rather than a fork, why not build options? This would reduce the maintenance delta to a hopefully manageable level. It is even something that could be done incrementally.