Stainless steel is rigid, but can also be brittle for tube. I would not do this if you drive where they put gravel on the road in winter, or if you EVER need to drive on gravel roads. Where a steel line will dent, a stainless one might crack, and then you're right back where you started with non-working brakes.
2012 Focus Titanium Hatchback
121,000 km, all stock
1990 Toyota Supra turbo
I think the cams are still stock...