Branding Irons are readily available for woodworkers to 'Burn in' their sales details to the various objects they produce. Our son-in-law produces various items and each one has his name and contact details burnt into the wood somewhere out of plain sight.
If both Brood and Super frames had the Beekeepers name and address burnt into them - say, a couple along the top and one or two on each side bars - giving , perhaps four locations identifying the ownership of the frame, this might be a deterrent to the Bee Rustlers.
This might be particularly effective if there were external signs stating "Warning - All Hive Frames here have been permanently engraved for identification purposes"
The thieves would have to somehow transfer the comb onto new frames. A tedious and time consuming process. They would also know that they would have in their possession (for a while, anyway) clearly incriminating evidence.
Our son-in-law's branding iron is electric. It's not very much different to a powerful soldering iron. I would guess it would take probably an extra minute to 'Brand' each new frame -and when compared to having to replace even just five hives and their contents, the time factor pales into insignificance.
Keepers with just a few hives could probably quite successfully burn/brand their frames by hand. Even at an 'Out Apiary', a gas powered soldering iron could be used.
I wonder if this might help you sleep to better at night.
Kind regards,
Malcolm B.