I just had this random thought. Would it be possible for them to make an F25T12 in a 48 inch length that is used on a ballast for the appliance F25T12 as a reduced wattage variant for the F40T12 for preheat that is made for 120v? If so, what starter would it require?
I dont think so, at least not with good efficiency and ease of starting
the 33 inch F25T12 was introduced not initially as an appliance tube, it was actually introduced and intended to be a regular tube as part of the the regular tube lineup, but critically it was explicitly designed to be the longest T12 tube one could make for 120V mains series choke operation with good efficiency, hence the slightly odd length of 33 inch, if you search the gallery there are couple F25T12/33 inch half-pipers on here, from when these tubes where considered regular tubes
they only really became appliance tubes a bit later on when they failed to take off in the general sector
and as an aside, the 4ft 25W F40T12 tube you see from time to time is a very different sort of tube spec wise to any other F25T12 tube, it runs at 103V 250mA, its not a low arc voltage tube and cannot be run off 120V
think of it as an F40T12 that someones fitted the cathodes of a F32T8 into
its explicitly designed for the cheap low power rapid-start ballasts found in Residential F40T12 fixtures from the 1980's onwards, so it maintains the same arc voltage of an F40T12, but is only rated for the current those sorts of low power ballasts output
