Yes, it can be done but it requires several things: long veg time, vertical, stacked lighting, and tall, high yielding strains, using Heath/Marlo's vertical scrog with wall trellises in a room with high ceilings, and hydro (Hempy buckets or DWC) I know, because I have done it, and really don't care if anyone believes it or not. I had 22 plants in a 5X9 room with 10 foot ceilings. 20 plants were vegged for 2 months (Critical Jack, a very high yielding strain that grows tall) and 2 Super Lemon Hazes that were vegged for 10 weeks, possibly a bit more. Lost track of exact veg time on those two, but plants looked as big as Xmas trees. One yielded a pound, and the other, just under a pound. The Critical Jacks all yielded over 8 oz each with 2 month veg. That's 10 pounds plus right there just for the Critical Jacks (Critical + X Jack Herer: Critical+ is Fruity pheno of Big Bud). Some of them were 10-12 ounces, smallest was 8 ounces. They were placed right against the walls all around the room, with vertical bulbs hanging in two columns in the middle. As branches moved outwards towards the lights, they were tied back to the wall. The two huge Super Lemon hazes that had extra veg time were standing in the middle of the floor with vert stacks on either side. Huge buds top to bottom. Fed with Maxibloom, Boost, and Bloombastic in flower. Buds were all flopping, so had to be tied with string, like they tie Xmas trees. Lights were within 6 inches of some plants. Anyone can do this, but it takes special strains, long veg, and vertical stacks. Also, were fed daily to run off, so had freshly oxygenated water all the time. They would suck the pots dry daily, and seemed to love that wet/dry/wet cycle.
For the doubters, grow some tall (at least 8 feet) Critical Jacks, and then talk to me. As far as I know, it's the highest yielding strain there is, although I haven't tried them all. Highest yielding I have seen. Virtually all the cubic footage in the room was used, and the Super Lemon Hazes had to be pulled out of the room daily in order to get to the other plants. They were on casters for that reason.
By the way, the object of this particular grow wasn't to set any records. Had broad mites in veg, so veg time had to be extended until the mites were eradicated, otherwise, I never would have vegged that long. The 2 SLH's were survivors from a previous run that were mostly destroyed by off gassing.
So, go ahead and flame away.
Forgot to mention, plants were grown from seed, not clone. Seeds give more vigorous growth by far, in my experience.