[broadgage]

60 watt circular fluorescent tubes are still readily available. A quick look on ebay shows a number of sellers offering them at about £10 each, cheaper if buying several.

I rather like these old circular fittings, some types used two lamps of different diameters, to give more light, or a choice of lighting levels via selective switching.

I also recall circular fluorescent fittings with a central GLS lamp. Sometimes found in cinemas and theatres with the GLS lamp being connected to a central battery emergency lighting system.