A-Cat Sail Innovation:
In 1988, Greg Goodall and his brother designed a sail with a wishbone/boom system which was quite similar to Randy design at the bottom.
The boom was half a wishbone from the mast until mi-chord of the sail and then a basic alloy tube was soldered just like an half boom
As a result the fore part of the footsail sweep the trampoline and you have a vertical "step" in the footsail
and then the remaining horizontal part on the sailchord.

"Boomless" is a consequence of this design, the alternative is the Greg Goodal wishbone/boom.

I would like to mention than 20 years ago the BIM A cat were also boomless, the consequence was a "give-up" in windward angle as a consequence of a "fat" sail section at the foot level, (More induced drag I guess)

Also more embarrassing, when you released the mainsheet in the gusts, the sail started being "fatter", therefore more powerfull before to open at the top.

In addition, the downhawl tension was much less useful without boom ie: sails twist more easily under downhawl when the footsail was tighten flat with a boom.

Hope it could feed your thinkings

Cheers

Erwan