Ake:
Probably no one has tried because there doesn't seem to be enough bang for the buck.
The DB reflector on a DB 6AA wired in serial can handle W/A bulbs generating up to at least 250 L. The 8X head and LA generate 110 L.
All (to me) interesting DB mods have involved wiring in serial. I'm not aware of any high amperage T-2 1/4 or T-2 1/2 bulbs in the 3.7 V range. Carley has a high amperage 3.7 V T-1 1/2 bulb, but I'm not inclined to diddle with adapters for it.
Specifically, Carley has a 3.5 V 2.30 A Halogen T-1 1/2 bulb #1122 rated at 50 hours and 135 L. As and when my 110 L 8X LA burns out I'm inclined to try to rebuild it with one of these 135 L Carleys. Brock's page says that the 8nx actually runs at 3.55V and 2.05 A, so this bulb's electrical characteristics seems perfect for the purpose.