Ur trying to save space on the root end of ur girls? I'm not experienced myself, but iv seen a hydro system built from inverted 2ltr bottles with the cap ends screwed into pipe for flooding in an issue of HT mag years ago. The author reported that the roots actually grew down into the piping itself with no adverse affects. I'd image a soil system would just quickly become rootbound and stunt her growth. I'm assuming u intend to grow into a screen to manage vertical growth and u'd probably run into this problem before the mesh filled. However with a hydro rig this would probably function. I'm a soil man myself but the hydro guys can probably give u abit more advice from experience. Interesting thought, I'm currently working on the opposite problem: i've loads of height but a tiny surface area. Lots of us are suffering from space issues, you definitely should read some of the scrog posts as this method saves a massive amount of vert space
I believe nearly any space can be turned green if you apply the correct tactics. And that is what we're all about!