As I did read the original request earlier, but did not have time to respond and there is much other information brought forth since, I'm going to comment here.
There is three large parts to a project such as the grubDAC: the schematic capture, the BOM and the PCB.
The schematic tells you what is going on. Tells you what parts are connected to what. In the case of the grubDAC, I was able to start from an existing schematic, so it was fairly easy to do this portion.
The PCB is really where the real work is. You're trying to fit parts to the PCB size. This process of doing the PCB also drives the BOM as you are trying to get certain size parts to fit in certain areas. You may have to tweak the value of a part to get the footprints you want.
Compare the two following pictures:
There was a lot of work to get from the one board to the next - I have about 15 iterations in my files. That is why it took about three months of working with tomb to get the board into production at Beezar. Doing things like making sure it will fit in all the cases that we want it to, that every external corner of the board is curved, moving vias a mil at a time to ensure that they are placed in exactly the right spot, adjusting thermal reliefs to ensure that currents are going the best path, etc.
Now about releasing information to the community:
Schematics are released as they are important for builder to build and troubleshoot the boards that they are working on. amb also notes that they are great source of information to learn how a circuit works. I have learned tons by looking at the schematics of others. Take a look at a PCM2707. There really is a limited number of ways that you can implement it as a USB to I2S converter. So many peoples designs will look similar. The onus is for the designer however to understand the chip. You can carbon copy someone else's design or you can read the datasheet and figure it out yourself.
PCBs are again something that is "released". A designer lays out a board and then releases it to the community as a finished PCB. You see it for yourself. You can see how the traces are laid out and the footprints of the parts that were chosen.
I initially built the grubDAC for my use as a present to my dad. Turns out that some of you like the extra boards I had run. I can honestly say that if tomb hadn't offered to carry the boards at Beezar, I'd have likely killed the project after the protoboards as I'd move onto the next thing that I'd want to build. That has nothing to say about how I feel about the grubDAC (which is that it amazing DAC for its simplicity), but more to say about the fact that I personally don't want to have to do the work of selling PCBs day to day.
rds is right as well. I'm willing to support a board that is designed by me and provided by me. I've built them and I know they work. If someone takes a board of my design, does slight mods to it that do not work and passes it off as a grubDAC, that is not good for me or my boards.
As an illustration of that last point, you may want to read this (especially point 3 of the first post):
DIYHiFi.org • View topic - "What's all this IP stuff about, anyway?"
There are those that will take a posted design/schematic/board and try and make money of it and leave the support to others. I'm not really cool with that.
There is another thing as well. Beezar is setting up to make kits and ensure availability of parts for the grubDAC. This take money and not a small sum of it. While this really is not my expense, I'd like to continue dealing with Beezar and am not going to do anything to jeopardize that relationship.
Every designer has his own reason for doing things in a certain way. I highly doubt that you will get a board file out of any designer for any active design. There are a number of designs that have been "given" to the community (see Headwize), but you still have to do your own PCB for most of them.
So my take is that while a design is active with me, I'm going to keep the files private for many of the reasons noted above. I'll support, help develop it and make it better. If I take a design and consider it dead, I might just give all the files out to the community. Why not? Let others get into the details and learn from what I have done. But if I "dead" a project, it will be dead to me - no support, no involvement for some of the same reasons noted above.
At this point, the grubDAC is not dead, so the files stay with me. Doesn't mean I won't work with others for interesting ends.