Tried out a Blu-Ray player, Sony BDP S 190 for projection for our mirror-dome. Got more clarity on the dome over our earlier VGA output method. Most probably the improvement is due to the blurring in the earlier VGA signal due to the cable length, while the Blu Ray player uses HDMI, and hence an all-digital signal path.
In case someone is interested in using this technique for "pre-warped" mirrordome projection, it is extremely cost-effective. Create the shows, warp as desired, put them on Blu-Ray or USB mem stick, no computer needed for playout.