Please stop making me jealous. The best I can do is a 140ps/4GHz Tek 1502.
One trick I sued to sell a surplus one at a harvest was to have a 20cm long wire[1] and run two fingers along it. The two fingers were clearly visible on the display
Before anyone thinks that's ridiculously fast, I've measured jellybean logic with a ~250ps transition time (74LVC1G family). Yes jellybean logic hits microwave frequencies; deal with it
[1] actually a microstrip, but that doesn't change the point.
I managed to pick up a 1502 and really like it. It's much more portable. The 11801 is a beast. But oh so cool. I bought one after I bought one of Leo Bodnar's pulsers and saw the supplied test printout using a CSA803A and SD-30. I had to have one and managed to get one for ~$150. It required reseating all the connectors several times to get it to boot and run the diagnostics which revealed the NVRAM had failed. Once I replaced that it's been fine since.
Sadly, there are no schematics available. The Tek Museum has all the records from a member of the design team. But the lawyers don't want to vet the material for release. There is a bunch of 3rd party stuff in them.
Happily, I later picked up a 2nd unit, so I've got a parts mule if I run into problems. Even better, I now have 4x SD-22, 1x SD-24, 4x SD-26 and an SD-32 in an SD-30 enclosure I bought on ebay from Tek. It has the 2.8 connector and the scope reports it as a 32. My guess is it was a prototype to test whether changing the connector would increase the BW. I have a 2.8 to 3.5 adapter on it and that reduces the BW to the SD-30 spec. I've not done a detailed comparison and even if the parts are the same, the 32 may have required selecting the best parts.