The 1780R had several unique measurement features that can determine which waveform monitor to choose. The 1780R has 2 CRT's one for waveform and one vector display. If a combination waveform monitor/vectorscope is needed then a 1740A or a 1750A can be used as a replacement. The 1750A has SCH phase measurement capability like the 1780R. In addition, the 1780R has built in measurement functions and the capability of doing ICPM measurements for transmitters. If these types of measurements are needed then a VM700T with option 01 can be used as a replacement. The 1781R is the PAL version of the 1780R and the corresponding replacements are 1741A, 1751A, and VM700T option 11. Dual NTSC and PAL formats can be accommodated with 1745A, 1755A, and VM700T with options 01 & 11 installed.
For something that's more future-proof, I'd recommend the WVR6100 with option CPS or the WFM6100 with option CPS. Either of these units will work with PAL or NTSC signals and can also support SDI inputs in either SD (WFM/WVR 6100) and/or HD (WFM/WVR 7100). In addition to the basic waveform monitor / vectorscope capabilities, these units have a host of other features including gamut monitoring, triggered alarms, remote control, facility timing alignment, optional audio monitoring capabilities and much, much more.