However, there is reason to hope that the even larger
    European Extremely Large Telescope will have enough
    resolution (about 5e-8 radians? hard to tell from their
    official publications)

6-12 mas is the advertised figure (0.006" = 3e-8 rad). That's the FWHM for its adaptive-optics imaging camera [0]. If you look at the details [1], it achieves the best resolution (6 mas) in the near-infrared J band, and for Nyquist-sampling reasons the pixel scale is half that (3 mas).

[0] https://www.eso.org/public/usa/teles-instr/e-elt/e-elt-instr...

[1] https://www.eso.org/sci/facilities/eelt/fp7-elt-pub/wfi_work...