How competitive could a team of the best players from tier 2 &3 nations (besides Fiji, Samoa and Tonga) be?

If they had a bit of luck, they might be able to knock off the Italians in the Six Nations. I would say that they would be about 50/50 facing off against the Pacific Island teams. But they would be absolutely trashed by the Tri Nations teams, and at least five out of six of the Six Nations teams.