I just started fpgacommunity.com. Since only like 3 people read this blog, I suppose the community will be small :) This along with fpgawiki.com will soon be hosted on a different server (when I get back to MIT) and then I plan to spread the meme through mailing lists and usenet groups. I think if there was a tighter community of FPGA users and developers, launching fpgaos.com as a community open source project might actually be feasible.
A few people have commented on why I would want to make the FPGA OS open source. The primary reason is that closed source is counter-academic and creates a barrier to adoption by those who would only use open source (meet the Linux community). The major barrier to FPGA computing is the lack of awareness among computer scientists, and closed source software tools exacerbate that problem. Also, open source guarantees that the best developers out there will have access to improve the code.
It may seem that I'd be missing a huge economic opportunity by going closed source, but if I place more emphasis on advancing computer operating system technology, money will almost definitely find its way to creating new applications. Even though transparancy is the goal of the OS, there will be an awful lot of code that could be optimized for concurrent execution even after an OS is complete. This will certainly be a non-trivial task, that will greatly reward those with expertise.
The amount of coding required to build an operating system for a reconfigurable computer is also way too massive to consider building without the concesus and assistance of the wider community. If everyone "agrees" on the OS then everyone will use it too, which means the effort won't have been wasted.