Styx said:
[The two BJT's example will actually work. BUT again you would not use it in practice.
Yes you would, and it's very common practice!. Obviously NOT for controlling large loads, but for small signal uses - where a latching circuit is required. It also has the advantage that it can have two 'gate' connections, so can be switched from either end.
In fact it's so commonplace that you can buy them in a single encapsulation (obviously made from just four layers of silicon), they are called "silicon-controlled switches" .
If you have a Sony TV under 6-7 years old?, it's almost certain to have a pair of transistors wired as an SCS (silicon-controlled switch), used for latching the protection circuits. That's an obvious current use, but they have been common in TV's since the 1970's.