I need the bar shortened. I'm exploring whether or not this will work, and if it's cheaper than a custom sway bar.

Two spot welds on the very end of each half is probably not going to ruin the steel temper of the entire rest of the bar.

Another strategy might be to cut some female spines into each half, and spline the two ends back together. I don't know what this might cost either.
Some Jeeps have this feature, disconnecting the two front sway bar halves.