There does seem to be a resurgence of interest in headphone amps. Headphones seem to be the only thing keeping two channel audio alive. Kits are a different matter. As Wayner says, kits are largely a thing of the past. I have seen it said that it costs just about as much to 'kit' the parts as it does to build the completed product.
As someone who has enough skills to stuff a board from instructions and follow a wiring diagram, I would do it, but I may not have much company. Pre stuffed boards, I don't know if that interests me. I would say that if it could be designed to fit in a readily available chassis, rather than tooling a purpose-designed box, that would help.
As an aside, a headphone amp has a relatively easy job to do, and I don't know why one should cost $600 or $800 or $1K. I may even un-mothball my Versa Kit line buffer and re-do it in the headphone amp configuration. Only thing is the value for the volume pot is not given in the Audio Basics article (what is that value, Frank?) Not the 'latest and greatest' but I bet it would still give a good account of itself- like I said, a headphone amp has a fairly easy job.
