Learn English – Does anyone know any examples that use this function or can write a simple example oneself

Whether or not it's "grammatically correct", at least here in the US, people say this kind of thing all the time. Something like:

Maybe I'll come by next Saturday?

is definitely a question, one that is asking for permission or approval. Asking:

Maybe I can help you?

is the same as asking "Can I help you?" but with more uncertainty whether you want or need my help.

That being said, you shouldn't confuse this with the "rhetorical question" structure that is a statement:

Maybe you should have gone to the bathroom before we left the house?

This is not a question, but a statement saying "It would have been a good idea if you had ..." Similarly:

Don't you think it would have been good to go to the bathroom before leaving the house?

Prefacing a question with "maybe" is informal, and is more common in certain cultures and dialects than others, so I would be careful using it -- especially since the regular question structure is always acceptable.

In the first case there's a comma missing, in the second case you put a linking verb at the end of a sentence. The latter is not incorrect but it sounds forced and it's unnecessary. As William Safire wrote "If any word is improper at the end of a sentence, a linking verb is."
I'd recommend the forms

The question is what my chances are to break even.
The question is, what are my chances to break even?

The first is a statement, the second is a question. Of course if you want to go with

The question is what my chances to break even are.

you can, it is technically correct and formal.
Now, in the second case the sentence fragment "what are my chances to break even" is a question in itself, so using it with "The question is" is informal, especially in writing, and it may be considered incorrect by some. It's fine most of the time, especially in the US, but if you want to go formal for certain, I'd recommend breaking it into a statement and a question, something like

The question is simple. What are my chances to break even?

You can also use a colon

The question is simple: What are my chances to break even?

But be careful with that, you can't use a colon after an incomplete sentence, so

The question is: What are my chances to break even?

is incorrect, although in speech there's no difference between this and my second recommended sentence.