Curved computer screen?

Columns. . At this point SimsArch has done it better than me, but columns are what you use to make a wall look properly curved if octagon segments aren't gonna cut it!

It's not to look like a wall, but to actually be a wall.

That means by all means and intent the game treats it the same as any other wall. It must be paint-able with any wallpaper, normal sims must not walk through it by default, you must be able to place tiles around it in the same way as other walls.

Good luck!

Edit: On a slightly different note, just saw the builds you've posted... makes my builds look like crap. Some seriously good work there[1]!

[1] Within game limits.

If Zar says you have to use columns - then you have to use columns. End of Story.