I just re-profiled some some BC Lyve canvas with my Munki, this time setting it for v2 profiles. Scum dots disappeared, and now the white border is just that, as one would expect. Printing on an Epson 4900 via Photoshop CS5 and latest Epson driver, Mac OS 10.6.7.
The only thing that changed is the version of the profile, cyan border with v4, no border with v2. Now that I have both profiles, I can reproduce the behavior very reliably. Looks like I have some more re-profiling to do...
Thanks all for the tips,