A new build (5) of the upcoming version 1.1 is available for further testing for Windows users at
http://supercoldmilk.com/ac3dplug/greeble.html .
This build has an option for "non-distorting" custom greebles as suggested by tbd, above.
The left geometry shows this option enable, the right shows it disabled.
The drawback to non-distorting greebles is that they don't distribute as randomly on "skewed" surfaces and triangles. By "skewed", I mean surfaces that have 4 sides but don't really look rectangular. On such geometry, non-distorting greebles tend to gravitate toward the center of mass of the surface.
Please advise if you have any trouble with this build. If I don't encounter any problems, this will probably be the final build before the 1.1 release.