I am far from an expert on the Renault engines. Actually, I know very little about them. You are correct that (at least as far as I know) all Renault engines fitted to Europas were non cross flow. However, modifying the Renault engine to crossflow spec was common. The Renault engine is very light (lighter than the Lotus/Ford Twincam engine), and with proper mods, including a crossflow head, could easily make more power than the Twincam. I don't know if the crossflow head automatically assumes Gordini parts and assemblies, but it would be worth a google for Gordini to see if more can be learned, especially if you plan to modify your Renault engine, or maintain a Gordini modified engine.
Hopefully someone with proper knowledge of the Renault and Gordini engines chimes in here to give you more solid information.
There is no excellent beauty that hath not some strangeness in its proportion.
- Sir Francis Bacon