Hello Jason
If your MBP is a 13 inch model, I would have no hesitation in recommending the Think Tank UD35 V2.0. It will take your gripped body mounted with the 70-300, hood reversed. There's ample space for two lenses and a flash too and the MBP can go into the rear compartment. It occupies a small footprint too but therein lies a dichotomy at least IMHO. The bag will get heavy because of the concentration of weight onto a smaller area. However if that is not a consequence and you are happy to buy new at $9.75 more, I would say the UD35 would meet all your needs, MBP size being as stated. You can also look at Amazon for ' used - like new ' items and depending on their condition, could represent excellent value.