Perhaps some member of the old Polish noble families of approved manners could be found among the Sobieski of Czatoryski families
I am more in favour of the Wettin (of Saxony) house. After all, they gave Poland two monarchs (Augustus II and Augustus III) who reigned over the first two thirds of the 18th century. Then the Third of May Constitution of 1791 pointed to the Wettin house to start a hereditary monarchy in Poland upon the death of Stanislaus August Poniatowski. Next, Napoleon Bonaparte, while giving the constitution to the vassal state of Duchy of Warsaw in 1807, made a duke of the Wettin house Head of the Warsaw Duchy. Thus it is the Wettin house, in my view, who should again step upon the historical path of the Polish royalty shown in 1791 by the independently passed Constitution and then by Napoleon (whom a lot of Polish people supported) in 1807, had any such idea as the restoration of monarchy to Poland came to existence. However. I am not sure if anyone of that house is still alive.
Were the Crown Jewels ever remade in Poland?
No, they have never been re-made. It would be quite difficult as there probably exists no patter on which they could be re-modelled. As far as I know, after having robbed them from the Wawel Castle Treasury in Kraków in 1795, the Prussians took them to Breslau (Wrocław) which town they conquered on the Austrians some time earlier, that is in 1740. In Breslau they remained for some time until one of the Prussians kings (have forgotten which one) decided to melt them into gold and use this gold for minting Prussian coins. Quite disgusting, I must say, but the Prussians were a rather practical nation, it seems.