on what basis do you loose your V-Speeds if reverse were to be used during taxi out?
Until JM comes back- I can't find a FCOM reference but certainly in the event of an RTO in the
sim on both the aforementioned types the V speeds are "wiped" from the FMC, quite what the trigger is ( RTO autobrake operation, REV Thrust being selected, or sim re-position) I'm not sure...
PM
How about single engine taxiing as a way of keeping speed under control?
In the context of taxiing to the runway for take off FWIW on some types (certainly at least one heavy I know of) there is a limitation that you can't single engine taxi if you are above Maximum
Landing weight