If you are looking for something flexible, that you can grow with, you might want to check out the OMS IQ Lite pack/harness.
OMS IQ Lite Backpack Harness
It has no rigid backbone so can pack down very flat.
It is set up to accept 2 cam bands.
If you start diving coldwater and/or want to get some of the additional weight off the hips and further up, you can just slip a SS plate into the integral slot - easy.
Pick your wing and swap as/if necessary.
Pick your weight pockets.
Last year I used an older OMS IQ pack (which is the heavier, older version) setup with the velcroed pull-to dump Zeagle Rear Weight System (on the waist belt, at the very rear
Zeagle Rear Weight System) (Actually, I just switched to similar dumping style OMS pouches with integral accessory pockets, but they are bulky and heavy). and a HOG 32# wing.
That will soon be going to my son as he outgrows his SP LiteHawk, and I have an new, slightly larger IQ Lite that I will probably run with the the 35# Vintage Double Hose Argonaut Wing.
Store | Vintage Double Hose
The DiveRite TransPac is similar, I believe, but without the ability to slip a plate inside.
Admittedly, the bolt-on wings will be a bit heavier and bulkier for travel because of the inner bladder and outer cover than the bladder-only of some of the ultra-lite integrated back inflate BCDs. Trade offs for durability, configurability.