So I see two solutions:
1) See if more developers come along for other architectures. This isn't something we can "make" happen, unless someone's got a rich uncle who's willing to pay them! We should make it clear we're looking for help, and if people want to help, they'll come.
2) Reduce that 2x to something smaller. This *is* something within our control.. we can try to solve the technical problems which currently make it hard to develop for multiple architectures.
This is meant as a starting point for further discussion, and also a means of conveying, for instance, why I haven't started building for x86_64. I'm not even running an x86_64 box, even though most of my computers are Athlon64s. Since I have to choose between developing and testing on one or the other, the barrier is very high. Let's try to make it lower.
I see a potential third option. That is.. Separate the x86_64 branch into its own support structure, effectively creating a sister distribution. They would manage pkgbuilds for that architecture, again separate from i686. Still provide infrastructure, but maybe make them a bit more self operating. More like providing a 'project' status to it, than making it part of mainline. When that branch reaches enough critical mass, and has enough support devs, *then* merge it into more of a single umbrella distribution. At that point, the supporting tools and underlying workflow *should* be more capable of dealing with needs. My fear is that the x86_64 branch may have been brought on board before there was sufficient infrastructure and support for it in the core distribution. I am still new here though, so maybe this is just me not seeing all the pieces. Certainly correct any of my erroneous assumptions.