Had my thinking cap on and came up with this. Do you think it would work?
Freeze a berley mix go fish guts, tuna oil and whatever in those cubed ice block trays that everyone has in there freezer. Once frozen drill a small hole through them and return to freezer. Now they could be used like a running sinker on the trace between the swivel and hook or above the swivel.
You can cast with it, then the Berley block would melt where you want it( near the hook). And you are fishing as light as you can. Sounds alright to me, anyone done this?