Just thinking out loud here, but..
Would love to see Indigo consider some kind of dedicated server "appliance". I'm thinking along the lines of a Raspberry Pi which retails for under $50 easily with a power supply and a simple plastic enclosure.
What I envision is a "run-time" version of Indigo that executes schedules, handles devices, and the web server that supports the RESTful interface and Indigo Touch / Control Pages. All the configuration, user interface, rules building, etc. would still run on a Mac and be downloaded into the Pi. So a Mac would be used as the UI/configuration workstation, but would not be needed for the running system. (I suspect that the "run-time loop" of Indigo, is relatively small and would be possible to put into an embedded device.) This would be a great way for systems integrators/installers to get more people using Indigo as one could bring a laptop to the client to configure/make changes, but the hardware investment for the consumer would be much lower.
The problem I see that is many people simply view the cost of a Mac (even a Mac mini which new is $500 without keyboard, mouse, or screen) as much too high an entry-point. I disagree, and think the value spent on a Mac plus Indigo Software saves hundreds or even thousands of dollars in the long-run, but it is a tough sell and will only get harder with Apple HomeKit becoming decent (but not great) with the iOS 10 release and the new "Home" app. (Not to mention Samsung building the SmartThings hub into every TV they make and other cheap consumer hubs/bridges becoming more popular.)
I know a Pi is quite powerful and certainly could do the job. I would even say a MVP (minimum viable product) might be to only support official devices (Insteon and Z-Wave via USB modems/controllers) and not support 3rd party plug-ins. I think Pi's easily run python so plug-ins are certainly possible, but maybe the MVP would be a good test of viability and less effort to at least try something in a 6 month rather than 6-year timeframe.