Please send me link for XVFB Source package for AIX
XVFB is part of the AIXWindows system and - this might have escaped your attention - copyrighted by IBM as the rest of AIXWindows. You will perhaps get the sources by making IBM agree to sell you their AIX business.
If you just want to install it you might be interested in this link.
I hope this helps.
bakunin
is XVFB open source ?
Did you read what Bakunin wrote?