Greatsword of throwing and returing, armor with armor spikes. Feats: ambidex, two weapon fighting, point blank shot, rapid shot, weapon focus: greatsword, specialization: greatsword. Full iterative attack with the greatsword at -4, armor spikes at -4, step back (5 foot) throw greatsword. That is 4 attacks at 4th level and perfectly legal.
Now, will a DM allow you to do it? Maybe, but that doesn't every one will. That also doesn't make it illegal by the rules.
Allowing bowmen to be able to threaten an area around them can be done with armor spikes without a "free hand". So, I would allow the use of a spike gauntlet for AoOs. This doesn't break balance, it rewards PCs for thinking about weaknesses and trying to compensate. The amount of damage delt this way is going to be minimal, and the swing is going to be made with penalties from rapid shot if used the past round.