Hi scottduffy.
I would be cautious about buying a huge one with the aim to carry everything. Eds advice about keeping heads and legs separate is good advice and usually easier to achieve with two separate bags. It's easier for storing the kit, car transportation and moving it around on location, than it is having everything in one big heavy bag. Splitting the weight across two bags makes carrying easier and if I have to move my kit any distance I use a lightweight wheeled luggage trolley with the two bags upright and secured with a bungee. Something else worth bearing in mind is that you will probably need to transport additional bits of kit for your lighting setup. For example, I also take: mains extension cables, multi socket block, rolls of lighting scrim and lighting gels, black drape, shower curtain, gaffer tape, black-wrap, light-meter, radio trigger kit, etc. My experience is that its a lot easier to distribute all this additional stuff across the two bags, than trying to put even more in the one big bag.
I hope this info is useful Good luck
Sam-D