BS, you've been able to get panel grips for markers for yonks. Dye up until recently used to do solid flat panel grips, might be able to pick up some, although not for an Angel (i think)
Doesn't the E-Mag use flat grips? And WGP recently released flat panel grips for the Eblade/WorrBlade. I wouldn't be surprised that because of the recent upsurge in their usage (cos of timmys) that more companies release them for fitting on to other markers.
Although it doesn't quite answer you question tom, the fact remains.