Pending update: I've prepared some textures for many of the new circuits and related components that were added in GT 5.09.28 (and tweaked in newer versions), with text overlays to indicate which circuits are used (primarily) for which power tiers, inspired by a texture pack made by Sapient and shown in this post in the IC2 forums. Since I can't claim the concept as my own, I've asked for permission first. If I don't get a response either way by Tuesday (Halloween), I'll go ahead and put them up anyway.
Also, a heads-up with this, especially for modpack texture patch makers: this will also override the two circuit textures from IndustrialCraft 2 so they'll fit better thematically with the rest of the GregTech circuits.
Edit: it has been about a week since I asked Sapient for permission, and I did not get a response either way, so the new textures will be up shortly.
Post a new thread here if you've made a BDcraft styled complete patch to fully support a Minecraft mod.
Okay, GregTech CE patch is up now (see first post for links), not heavily tested. Please only report non-upgraded textures if they're actually available in the GT 5.09 patch or can easily be pulled from other patches (e.g. IC2). I don't have the skills to promise new textures from scratch. If you can tell me the texture path used in GT 5.09 (or other mod patch) and the new texture path for GTCE, that would save me some time. A GitHub pull request would be even better.