Thanks for replying MagnusIlluminus - appreciated.
I wasn't aware of some of the context around this so that's appreciated.
Really this will only be for close gaming friends, for use at home, so don't need too much detail.
I think instead I should be able to bodge in other units to count-as Heresy units. For example, Blood Angel assault troops (or even Khorne Berserkers actually) as Pre-Heresy Berserkers. Imperial Guard artillery units as Marine artillery units etc.
Hopefully I'll be able to get a close-enough approximation with a standard NetEpic unit card doing that.
Thanks again for the reply, I'll stop looking for something that doesn't exist!