Give it to me straight doc, will this hurt?
Generally speaking, companies hire people who have the skills they are looking for. They don't much care where you got the skills that they are looking for. Did the New York Times look down on Nate Silver because he learned his skills through baseball analysis rather than working for an established political polling firm? Of course not!
So why do employers look down on unemployment in a candidate?
When you have a billion CVs in front of you, and need to present the best ones to your boss, often you will look for shortcuts. If you can't explain a significant gap in a potential hire's CV when there are equally qualified ones without it, then your boss will ask questions.
"If he/she was so qualified, why couldn't he/she find a job?"
"After such a long period away from work, can they still remember how to do the job?"
"What does it say about his/her decision-making if he/she quit before finding another position?"
So if you're in charge of filtering the candidates, and you can't answer those questions, there's a good chance that you'd decide to throw some of those CVs with blanks in the bin. As with the linked question you provided, the length of the gap and the reaction will depend on the company/person.
Telling a story
The best way around this is to preempt those questions by giving them a good reason to see whatever time off you took as a bonus. If going to school full time is the reason, you can stick that in your work history with a note see Education, or if a side project, explain the side project right in there. This will show whoever reads the resume that you were accomplishing something even if not connected with a steady paycheck.
This is all dependent on you actually doing something of value with your time. I'm worried that your question sounds more like, "What happens if I fail" when you should be focusing on the value if you succeed. And you should plan to succeed. If that means you do it for now on the evenings and weekends to get your feet wet before jumping in, then do it. If that means setting yourself a goal of accomplishing task X by date Y on budget Z, then do it. If that means you need to work part time, sort that out first. If you plan on going to school full time, factor that in. The point is that you should look at what you want to achieve first, and focus on achieving that.
If you succeed, and develop the skills you need, then the employer should definitely not care.
If you met someone who could say, "Yes, I am one of the main contributors to project X" and you look on the net and see that they are, is that going to be less cool than someone who says, "I write code for mid-size company Y"? You just want to make sure you don't say, "Yes, I learned X at school, did Y on the side, and got a lot of great experience!" without actually having anything to show for it.
So worry less about the gap in unemployment, and more about using the gap to successfully develop the skills, and all will be well in the world.