I'm not an expert but if it's possible to save the block id do that and rebuild it with new pistons and a gasket kit and put it back together. The engine shop should be able to tell you if the rods are fine when they're connecting them to the pistons. Or another way, buy a block get it honed and put all your shit into it? Would probably work out the same price though.
It's kind of redundant to buy a second hand engine, heaps of stories about how it's a fresh engine with 60,000ks and never been boosted, only to find it's dropped a cylinder.