I made a Palatial house that occupies almost all the area of the biggest lot. I only went as as far as the outer shell. Towards the later stage of building I noticed that I cannot build anymore wall segments. But I also noticed that when I deleted some of the wall segments, I can build walls again but only of the number of segments that I deleted. Example, I deleted 4 segments of walls, then I can build only 4 wall segments again.

Someboby at TSR suggested me to test by filling the largest lot with walls criscrossing vertically and horizontally. It didn't even take one level on the ground of the largest lot to run out of walls.It seems that the maximum number of allowed wall segments is 2057.

I would love it if there is a mod altering this limitation.

I did a test lot on how many segments of walls that I can build. What I did was 40 segments on 20 rows on each floor, which brings it to a total of 800 segments of walls. I build the second floor of walls, and then a third floor of walls (I kept doing it until the game won't let me build any more segments. What I came up with is 2100 segment-of-wall limit. So, if there is some information that I could come up with, it would be useful, because I, myself, would want to change the limit to a higher amount, allowing me to build highrise buildings.

I believe that ther has to be a way to alter the game so that I can build more walls. Because NIGHTLIFE is comming out this fall, let's beg Maxis to change the Max of Wall Segments, so that I could build a city-like experience in the community lots, like a multi-purpose building for nightclubs, performance shows, casinos, restaurants, and more. And, I want to build bigger lots too, that are like 8x8, 9x9, or even 15x15. I believe that 5x5 is too small for complex community lots.

updates:

linking related threads together:
Can you run out of walls
http://www.modthesims2.com/showthread.php?t=86434
Limit in number of wall segments you can build
http://www.modthesims2.com/showthread.php?t=10907
Maximum walls... please help
http://www.modthesims2.com/showthread.php?t=49043
Wall Maximum Limit-PLEASE HELP!
http://www.modthesims2.com/showthread.php?t=90785
Wall Problem
http://www.modthesims2.com/showthread.php?t=36055
Wall segment limit
http://www.modthesims2.com/showthread.php?t=39011