  The angular resolution of the proposed Square Kilometre Array, SKA, must be
extended towards the milliarcsecond scale if it is to resolve the distant
starburst galaxies that are likely to dominate the radio source counts at micro
and sub-microJy flux levels. This paper considers the best way of extending
SKA's angular resolution towards the milliarcsecond scale. Two possible
SKA-VLBI configurations have been investigated and simulated SKA and SKA-VLBI
visibility data sets generated. The effects of non-uniform data weighting on
the associated images are considered. The results suggest that the preferred
option is for SKA to be extended to trans-continental dimensions. By retaining
50% of the array's collecting area within a region no larger than 50 km, the
surface brightness sensitivity of the array at arcsec resolution is hardly
compromised. In this configuration SKA's capabilities are impressive: in a
single 12 hour run, between 100-1000 sources will be simultaneously detected
and imaged with arcsecond, sub-arcsecond and milliarcsecond resolution.
