If you get enough people, someone in the group will always have a new and/or recently calibrated meter.
We could use a wiki page. Eyeryone who joins the group could add his dmm, including the calibration dates, to this wikipage. We send two or three standards in a circle always around, and everyone could enter the meassurements into the wiki page. If someone gets the standard, he can check his DMM against the others.
We do this in our country, and the shipping costs are low. Once a year we send a standard over the ocean to another measurement club and they send us vice versa their standard. In this way we could do a cross check.
I would join such a "measurement club" here in germany/europe. And I can offer hosting the wiki. Anyone interested?
That common site would be a good idea, and a necessity for the exchange / circle-comparison of calibration data. I doubt, anyhow, that it's feasible to disclose publicly, visible to everybody, such confidential data, e.g. about individual possession of expensive instruments.
The technical exchange could only work properly, if travelling standards / calibrators of highest quality would be available. DMMCheckers and alike, or lower grade resistors are not suitable.
Reasons for my opinion:
1. Even if one member only wants to "check" his lower grade instruments, like e.g. 5 1/2 .. 6 1/2 DMMs, anyhow, sufficient T.U.R. is needed, so you easily end up with 1ppm uncertainty.
2. These standards, as they are exposed to rough environment on their travel, have to be extra stable and rugged, otherwise you won't have the chance that you ever get consistent values, after their return to the place of origin. Therefore, this excludes any simple or cheap solutions for these standards, probably also LM399's.
3. This initiative for sure aims also at volt-nuts, who already operate at the <= 1ppm uncertainty level.
If the travelling standards are less stable / uncertain than that, it would be completely uninteresting for these people.
Under these preconditions, I'm basically interested in such a group.
There already have been several personal volt-nuts meetings with high grade equipment.
I personally prefer such events, over anonymous parcel shipping.
Frank