no. not for awhile... IBM/Hitachi is the only manufacturer to use a 5 platter design... maxtor, fujitsu and seagate have not maxed out at 4 for several years on all their 10k and 15k lines...
the trend is to go down in platters, not back up. It will take greater density to get more capcity than IBM/Hitachi.. and that density comes at the cost of seek performance quite often.