It has been done, but not in a privately-owned car yet to my knowledge. A few Mk3s have had it done.
I even tried to get testers for companies to use for brackets.
Attn: Planted Technology is looking for a 2012 Focus!
2012 YB Focus SE Sedan [featured in Performance Ford, Sept '14]
1992 BW Grand Prix SE Sedan [restomod project]