What do you want to haul? heavy lifter is subjective, build what you want to lift, dont overkill just because you can, I made the mistake and did a 2400 watt octo which was pointless as I was only needing to haul a NEX5 camera...so I downsized to a hexa which is portable
If you want to earn a living from it, plan to completely replace your gear once a year for crashes etc...
Ive just brought a couple of $37 fold-able hexa frames from omgfly which I will tinker with and will sure do the trick, I will also look at getting a DIY Xaircraft hexa which can more then haul my NEX5, your 550 is great for throwing around a point and shoot...I even think it could haul a NEX camera!
Dont get caught up in the heavy lifter game as its overrated IMHO, build what you lift
Cheers!
Jas