Not to try and steal any sort of thunder, but ive used a lawnmover v-belt for almost the past 3 years on my AAZ powersteering 
Deffinatley have not had any issues, and its a hell of alot cheaper as a bonus to.
So how did the lawnmower belt worked for you? What size belt and where did you use it? I will give you all the credit you deserve, only if you had shared your idea.

Please post a link.
I have been driving around on the 6827 PowerRated lawnmower belt on my power steering and so far so good, no more squeal when turning the wheel lock to lock at a standstill, even though the belt is a bit on the loose side and at the limit of the tension adjustment. These belts do not stretch as much as automotive belts and I hope it will not loosen up. Belt looks good, not flopping around. Hope it stays that way.