Speaking as one who has done a number of SOA's including 2 on my CJ-7, its actually a good way to get a lot of lift in a leaf sprung vehicle. But it should be well thought out and it will cost a lot of money to do right.
On the X I just don't see the point. You'll get 5-6" of lift. But I don't think you could even fit a tire big enough to require that much lift without cutting the wheel well. Even if you could fit a tire that big on there, say a 37" tire, the axle just wouldn't be up to that type of punishment, if you run trails tough enough to justify a 37" tire. Now lets talk about gearing, axle wrap, the speedo, shock lengths a new drive shaft, etc. And that's only the rear axle.
However, I don't see any way to get debris in the axle when you are welding on the tube, unless you blow through it (but then you have bigger problems). I've never heard of anyone disassembling an axle housing just to weld perches on. I have seen a number of people weld perches onto an empty housing but only because it was already apart.
-Old Army