The short answer to your question is that to the best of my knowledge, there has never been a Concow speakers language survey undertaken, although there really needs to be one. This would be a valuable thing to include in your grant proposal, and if you would like, I can put a survey form together and see if we can get cooperation from the other tribes to have their members complete it as well, the education coordinators would be the best entry for this. Concow has never had any real and comprehensive resource mapping done, and it is a necessary step before any real recovery efforts can succeed. Lori Frazier got some ANA grants in the past for this, but there were some "difficulties" from what I heard. The other tribes haven't undertaken anything comprehensive, and most have done nothing at all. There have been no additional studies on Concow since Ultan in the 60's, and so there is nothing available from the academic community at this time either.
I could do this, as another component of my internship time, if you like. There may be some costs/expenses inherent from the survey process itself which would be reasonable to look for funding for in the grant you are currently working on. The forms are relatively simple, and the tribes each have their own processes for motivating their members to provide the information. It might even lead to some pleasant surprises. It would be nice to be able to identify some additional resources that are as yet unknown.
Now for the long answer:
There was a video of the first Concow Language Conference that had all but one of the speakers still alive at the time up on a panel with Bill Shipley. The only other one (full language) was Jack Johnson, and there are some other partial language speakers which help on some language development as well, and these include Adrian Smith, Paul Cason and (unfortunately :D) Wayne Nine, the three who organized the conference. Most of the the full speakers at that conference are no longer alive, but the still living ones included Virgil Logan, Franklin Martin, and Jack Johnson (of course). Paul was very marginal as a language speaker. Adrian is inflexible at times to work with although he is at least educated (he has a BA in Sociology and was a grad studnet when he quit, but that was back in the late 60's), and you know what Wayne is like.
Franlin Martin is deaf, and so it is difficult for him to be helpful, Virgil is good and has experience in language classes, and Jack has the best command of the language but has the fewest tools as an educator (not that he wouldn't be a good one with some support services). There are also a small number of Concow speakers in Round Valley who might be helpful, but there is a history of problems between people here and in Round Valley. A few years back Lori Frazier brought some of the Lincoln family over to help with Mooretown's very active language program at the time and evidentally they stole language materials and tapes generated by the project and took them back home for their own program - or so Lori told me at the time (this was one of the ANA "difficulties" I mentioned earlier). Regardless there is some serious bad blood there.
Even so, there might be some documentation generated by them in relation to language survey information as a result of their own programs. Another person making an inquiry might garner results (any one but Lori, specifically). Although Adrian has, in fact, asked repeatedly that a language survey be undertaken, one has not occured by any of the Concow language speaking tribes in Butte County to the best of my knowledge at this time. It would be a good thing to do, as it would provide the documentation you need now, and is a reasonable thing to ask for in your current grant request to clarify the language's current resource map. The video itself can be accessed and I could submit an affidavit to it's content if that will help. It is currently housed at the CSUC Merrium Library Special Collections, and I have copies. I have been slowly working on enhancing it for more usability as a language tool, but would rip off a quick copy if it would benefit you.
Additionally, there have been some individuals building language skills for their own edification that I know of. None of them are at any level of fluency, but some do have enough skills to expect they could help in a developing language program with young people. One example here is Eric Josephson's wife Kate. She isn't Concow in any way, but is very interested in the language and attended the Berkeley Summer seminar native languages program on behalf of the Konkow Valley Band of Maidu along with their chair, Patsy Seek. Patsy can't keep any of the language material in her head, no matter how she tries (and she does) but Kate shows a real talent. She also works well with kids. There are also people who have worked on the language classes over the years as part language speakers. These are also resources for a language program depending on their ability to work with other (younger) learners. One of my own suggestions for the future would have been to look into developing teen learners as coaches for the little ones. They are not only effective assistants in the learning processes of the pre-schoolers, but it helps develop their skills as well.
So, to summerize: as it stands we have 2 full speakers, one severely disabled full speaker, 3-4 nominal part to nearly fluent speakers, and an unknown number of very low level part speakers. This needs verification, however, and I'm hoping the verification process gives us a few surprises. There are also always the Round Valley Concow, as well. They are unknown to us, but they may have done their own documentation process. We won't know till we ask them.