Not sure why you'd want 5 - from what I hear the lvl 5 missions are doable by 3 as long as you have 1 dedicated logistics ship and he was pretty deep into the tree.

When I was playing 3 accts I was chain running lvl 4's with a CNR (Caldari Pilot) completely loaded out - it was permaboost. Second acct was a megathron with remote reppers, tractor beams, salvagers and remote repair drones. There wasn't a lvl 4 out there that could even really dent my shield. Made for some really consistant cash.

The 3rd acct was for hauling hauling hauling...