This way you generally can refi or sell and 1031 at the time you want that is optimal versus a short term loan where you are forced to sell or refi on terms in the market you do not necessarily desire.  

I'd recommend going to some REIA meetings and see if you might be able to find some partners with properties in desirable locations that could be prime vacation rentals.

I own a 3/2 in a desirable, middle-class neighborhood in Houston.

(and the next property I buy will put me over 100%) I mitigate this risk by purchasing properties that are in very desirable rental areas and in good condition.

Then, you've got your monster house, in, by your description, not the most desirable neighborhood.

I work full time and am doing quite well in that regard.I do realize that there is a very large risk in thinking that I can keep it rented and perhaps I am being a little too optimistic in that regard but I do know that the area I live in is highly desireable for young professionals and I have a few friends who have been very successful in keeping their properties rented in this area.

Well, at least properly imagine your circumstances, desires, and lifestyle if you had that kind of $$$...not sure I would have even understood the humor of this $3-400K ago.

This is not desirable for the syndicator.   

In my experience, homes with 3-4 BR and 3-4 FullBA are highly desired by young professionals and they will pay more, especially near a metro.

That way you'd be able to offer AC as well and that would definitely increase the desirability of your place.