ADMIXTURE's quite sensitive to the variability present in its sample data in order to be more precise about relationships. Representative samples from certain regions would definitely improve the resolution, particularly for smaller components.
Thus I'm asking for 23andme genotype files. Complete anonymity is guaranteed. No health information will be collected from samples, only ancestral info. I will identify each individual only by a tag with country of birth of grandparents and if provided regional origin as well. I do think ADMIXTURE's powerful enough for at least some regional resolution. So if a participant only wants to declare country of birth of his/hers 4 grandparents, that's enough but if you could provide regional origin as well (ie Cornwall, Munster, Bavaria) it would be much more useful.
I'm very interested in samples from Europe, like Ireland (particularly the Western part), UK (all, but more Cornwall, Wales, Scotland Highlands), Finland, Scandinavia (especially Norway), Iceland, Switzerland, Austria (especially Tirol), Slovakia, Carpathians in general (regions of Romania, Poland, etc), Germany, Ukraine, Iberia and France (especially Alps, Massif Central, Pyrenees) with regional identification. Plus people from the Americas with significant known Amerindian ancestry (tribe or regional-tagged please). Also any mountain or island region in the world not represented in my current sample. I know I'm naming several regions with few participants in other projects. So I'm not even mentioning Madagascar, Sami, Indonesia, or Australian samples with known or possible aboriginal origin.
Since I'm anticipating a slow start, I'll probably accept any sample that is tagged with certain regional origin of each grandparent. I'll be making an announcement at 23andme tomorrow (I'm Diogenes412 over there).
So what do I offer? ADMIXTURE analysis in possible Neolithic/Forager element runs I've been publishing. In the future I may be doing more regional and historically more recent stuff as well, if possible.
You can email me at firstname.lastname@example.org (or through the blog's email).