If you wish to digress on how FAR 61.3 requirements might (or not) be met with JAA or EASA pan-EU rules, feel free
Anyway, the FAA does not restrict its Experimental category aircraft territorially. It's entirely up to the foreign airspace what they let you do.
Personally, I doubt EASA will ever allow U.S. Exp Cat planes to fly over here. From personal discussions I've had (at the top, more or less) the whole drift of EASA is to be ICAO compliant. They even plan to file a difference to ICAO on the LAPL, which would make it ICAO compliant despite its GP medical, thus making it potentially usable outside EASA-land. And the US Exp stuff is sub-ICAO.
Now, if EASA introduced an Exp category over here............ that would be something else. I can't see it happening. I can see them doing a 750 kg class and maybe bigger stuff, which will be pretty well deregulated, VFR only. That will probably meet the requirements of most pilots.
In Europe, "IFR" is a 3-letter word which arouses massive emotions among the old fart regulators, which is why the IR has always been as hard as they could make it.