Since this is a lightweight backpacking forum, it probably isn't the best place for info on such a backpack.

There are articles on the home page of this site, left hand column on gear selection, but, again, they're oriented towards lightweight gear. If you're interested in lightening your load, though, there are lots of ideas on how to do so.

For any backpack, the three most important aspects are fit, fit and fit. The pack needs to fit you, it needs to fit your gear and it needs to fit you with your gear inside.

For high bulk and high weight, you definitely do not want a frameless backpack unless you enjoy painful experiences. I wouldn't recommend a frameless backpack unless your total pack weight (including the pack) is 20 lbs. or less.

It would help if you could describe the volume and weight-carrying capacity for which you are looking.