The way I thought about it was do I want to have the best return based on numbers or the best return based on lifestyle, and I ended up choosing the second.

Change your life style, live frugally and save more money.

If you were starting today, and lived my nomadic lifestyle, how would you approach real estate investments?

You can do well outside of the cities but you have to know your areas well and make it so it isn't a lifestyle issue. 

However, it seems that very few options exist (if any) that cater to “high-end” clientele (business execs, consultants, and others that value luxurious lifestyles).

You can probably live a better life style on 6k of w2 because of  Benefits  (health care being the big one)  Conventional loans are going to be tough, your income is going to be scrutinized more.  

I've become obsessed with the idea of using real estate to achieve financial freedom and to fuel my adventure travel lifestyle. 

I know there's not a golden rule for this and it varies by a person's lifestyle, and life priorities, I'm just curious what % some of you are running at.  

I can afford to come out of pocket $500 and still sustain a comfortable lifestyle.

It's a life style decision only.