H-1 revalidation means for certian type of visa,H-1 is inlucded,F-1 not, if you has got the same type of visa from out sdide of US, then next timw just mail it to DC and get it in mail,may take 6 months.
for those with status but no stamp, need to go to CA/Mexico/China to get visa.
I don't know how about other countries, but basically, you'd better do it in one of these place. Think if you are stuck in one place in Europe and has to go back to China....

Maybe Mexico is better than China, and it is said now you can come back with ur i94 if you are refused,
someone canceled their application at once when the officer try to check him/her.
:)
Problem is I don't know if you are refused and you walk back with ur i_94 then what's ur status?
maybe no one cares, but I just don't know.