- 1) Sell stock enclosures, and include a 1/8" thick plastic insert that fits the case perfectly, and can be drilled (and maybe tapped) for Hackers to mount their own PCB with hand tools. This would be easy, flexible, and simple to offer. Only the stamped insert is required if you use commercially available cases.
2) Design more of your PCBs in a standard footprint for a project box. I know that the breakout boards are all optimized for each application, but I would happily pay a little more for one that is easy to mount with consistent hole placement. A pair of holes 1" apart on every board would make them much easier to mount with standoffs.
3) Make the redboard conform to a nice rectangular hole layout (like this one http://www.serpac.com/userprints/330-430-cbg.pdf). This would be a huge advantage for builders, and would make it much more than an Arduino clone while still keeping it shield compatible. I can't believe the Arduino has that funky board outline, and everyone copies it!
As a bonus, if you offer a nice way to put projects in enclosures I am much more likely to buy more parts for my future projects instead of scavenging from old ones.