The Skylon FST is a great tower with a narrow stance. As long as you make sure you have enough reinforcement you shouldn't have any problems with this tower.
|Big Air Predator|
Some manufacturers try to keep the front to back stance wide to prevent issues down the road, like gel coat cracking. A wider stance allows the stressed area to be spread out.
Lets just be honest here..... Stance can be a big part of the tower appeal and design. If you don't like, or are worried about the stance, ask questions. Figure out what the manufacturer recommends before purchasing.
Just keep this little factor in mind when purchasing a tower.