Just a thought: A possible solution that's been around a while, but in another application. How about a dead weight counterbalance mechanism, like the old style sash windows weight/counterbalance to raise/lower the hidden/inconvenient space.

As stated, the hardware would need its own space. I wouldn't think there would be too much cabinet weight and (as Leon noted) stored material weight that needs to be supported. A little trial and error construction might produce a reasonable/inexpensive application for this dead weight lower/raise mechanism proposal.

Sonny