For LED Filament, there is no Eliptical shaped solution for the US market I know of. However Philips Europe has one on, so I think it is only a question of time, when one will be available for US Systems. It might be possible that, some manufacturers made them already and I have not found them. It might even be they appeared here on LG already but im not sure.

Hello
I have found an Filament replacement lamp:
https://www.lighting-gallery.net/gallery/displayimage.php?album=4041&pos=0&pid=182822

I’ve tried and tested 12 watt, 1520 lumen LED filament lamps in my restored GEC Nightwach 70 lantern, and they look perfect, granted not quite as bright as the 70 watt SON-E that came out of it, but given today’s rip off energy prices, I know which wattage I’d rather run in full time, all night use at home!

Screw in retrofits are fine. In fact, I'd rather see vintage lighting converted to LED if it means preserving the life of the light itself. In outdoor HID luminaries, this isn't as much of an issue as a vintage indoor table lamp made with plastics. The heat of incandescent and halogen or UV of CFL will increase the speed at which the materials degrade.