I believe...
If anyone takes a look at the their stock tachometer, you would see that the "official" redline occurs just short of 5500rpm. I would guesstimate that 5300rpm is the "official, from the factory, stock redline". Yes, it's possible to REV the engine beyond that printed line, and what XR7 dave is talking about is a fuel cut-off to save the engine, which occurs at the higher RPM.
Certainly with proper engine parts that are stronger and lighter and much better balanced, the theoretical maximum rotating speed of the assembly increases. However, due to the breathing characteristics of our engines, along with the low-rpm nature of our superchargers, many of the highest HP SC's generate their peak output under 6000rpm.
Can the 3.8L be built to rev to 8000rpm? Certianly. I've seen many OHV engines built this way. Can it do it using a Roots supercharger? Not really.
Wankels do not use a "crankshaft" per se. They use an "eccentric" shaft for the Trilobate (triangle thingy) to rotate on. I've seen a dissassembled Wankel engine and the eccentric shaft is very small and light. It really looks like a shaft from a 2-cylinder engine used in a garden tractor. So it's no wonder why it has a 10,000rpm redline.
Hondas: Because all of the engines are N/A ones, to induct the neccessary amount of air into those engines to generate the HP, you require higher RPMS. Honda engines are built to rev high and have a higher specific output. But within a very narrow engine operating window. Thats why a system like VTEC and VTEC-i, allows honda engines to be very streetable and broaden the RPM range.