I guess they could have the signal and ground pins side by side but then trying to probe anything not a standard 0.1 header etc would be a real pain. If you experiment with the accessory kit included with the N2796A you might find several probe/ground combos work quite well. And as already mentioned as long as it isn't exceeding the frequency limit from additional lead length(detailed in the manual) you can use the included header adapter. The bonus is you don't even have to hold the probe, you can just plug it in. I really like the smallest probe tip and the Z shaped ground wire combo on my N2795A.