You just drove your car off the road
Plasma vs LED/LCD, with all their merits re-hashed IMNSHO was probably better handled at the beginning of this thread You can search back through this forum to find many, many comments by myself and others.
To make things easier, I would stick with the assumption LED for now since your selection is much better, especially if you are looking at multi-system HDTVs.
Regarding 'multi-system enabling process', you would benefit from stepping back ten feet and doing some reading back inside the links I posted. There's no "slight of hand" involved here like you might see with a cheap external PAL->NTSC converter (more comments on these later). It's a legitimate built-in ability to handle not only 50Hz Euro content, but also 60Hz, given that the US entertainment market produces/sells a lot of things you cannot find abroad, and they only come in 60 Hz content for our TVs in North America. Use those two Sharp HDTVs you posted as examples- the 50Hz will be handled similarly. Other factors regarding PQ fall into play besides 50/60. It's difficult to say if those two perform equally well w/o testing it in person. 50 vs 60 won't be an issue at all, but likely everyday things like contrast, brightness, color saturation, handling of motion scenes, etc. [You might compare PQ of a Samsung to a Sharp. There's going to be some differences. Hint: there's a reason why Samsung is popular.]
Keep in mind that it's likely Cyprus has already completely switched their local broadcasts to DVB-T (=digital). That 'Com World' product won't help you tune in anything if that is true. So having the ability to convert PAL to NTSC might not matter w/o having a tuner. Also, remember the occasional pitfalls of HDMI-HDCP. It's entirely possible that an HD or Sat box in Cyprus won't play nice w/ your US HDTV if you have a rogue converter in the middle. Personally, I would only use a Euro sat or cable box with a Euro or multi-system HDTV.
FWIW, the DVDO Edge is generally considered the consumer model scaler to buy for great quality. It can handle a lot more than PAL-NTSC too. Not cheap though at ~$600.
Another question regarding warranty- are you a dual citizen? If not, is an American HDTV warranty accessible to you? And how would you find service abroad for an American HDTV model? (Is it offered per their terms?)
My final thought- if the American version was cheaper, and only had 5% better PQ, would it still be worth the hassle of not having it be able to be easily used as a 'TV' while abroad(?)