The problem is a challenge. I think it's mostly going to be for niche use, or it may even be completely useless IDK. But it is as stated below.
"Can we make a BJT circuit that will attach two or more Tri-state I/O devices with two different voltage levels, and still be able to do bi-directional communications passively"
The best I have been able to do is zener diodes (or several normal diodes) as voltage limiters, then buffer resisters on the I/O's like so.
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But this requires a 5 volt device that sees 3.3 volts as logic high. And some 5v devices absolutely hate this and will refuse to work or even burn up if you try. At first it seems like you should only need to simply amplify the 3.3v signal. But try it and you get a whole bunch of other problems in on top of the first one. At least from what I have seen, It's mostly problems with latch up a Roff has suggested. Also of note, and strictly speaking, the above circuit is not "true High-Z" capable since forward biasing the zener has a relatively low resistance to ground. But it is "Logically High-Z", which is close enough for practical use. And one can play with the resistors to tune it even farther when needed.
Another different way to go about doing things, is if you have a 3.3 volt logic device that is also 5 volt tolerant. But doing that is cheating. You don't even need anything to convert levels at all, just buffer resistors to save the outputs if and when both a high and a low exist on the bus wire at the same time. Plus not all 3.3 volt devices are 5 volt tolerant. But.... I don't make the rules I just break them.
Have you considered the problem having [two] outputs on the same wire?
I think your speaking of "bus contention"? Yeah I though about it, all I/O's would either have to have resisters on them to make them have infinite short circuit sink/source time. Or there would have to be some kind of synchronization system that completely prevents such a state from ever happening. I do not like the idea of doing some kind of synchronization, as it's more complex and defeats the purpose of the project. It would be better to do the fist circuit you posted as is. So resistors seem to be the better way to go.
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Above is a picture of a starting point schematic I guess, since that's what every one seem to want. It should look familiar, being a modification of the one you posted for me. Like I had said, there was no set in stone schematic and no particular project that needs this. It would be a nice niche circuit to develop and I could definitely put it to good use.