there were a few threads I've seen (literally 2-3 tops)
nothing much in them, except how they are kinda cool, and incredibly expensive.
http://store.rc4wd.com/112-Scale-Ear...15_p_1587.html 1/12th excavator +$400 shipping
http://store.rc4wd.com/114-Earth-Mov...er_p_2270.html 1/14th semi dumper (that is
ONLY for the trailer the $400+ or so semi to haul it around is not included) +$250 shipping
http://store.rc4wd.com/Robbe-MAN-TGA...M-_p_1850.html probably would need this to move that trailer +$60 shipping
and that is why there is not too much interest in them

if they were remotely affordable I think many people would buy them, but hell shipping alone for the excavator is half of what I paid for the car I drive to work [:@]
If you mean the cheap $60 toy grade ones I saw while searching for those I doubt most ppl here would give pay them any mind seeing more than likely they wouldn't last 5 minutes in the hands of ppl on this site