Yet there are certain neighborhoods that have a high share of 18 to 44 but a low share of rental housing units (green dots in the graph). 

What areas are you looking into @Quintin Green?

I have called many banks around my city and though, me getting approved hasn't been the issue, it's amazing what different products are out there.

For example:A clear or black (if you don't want anyone to see what's inside) acrylic wall-mounted suggestion box (both of which fit the dimensions you listed and even have a slot at the top for running wires out of):Link to product: Clear Suggestion BoxLink to product: Black suggestion boxOr just a plain acrylic lockable box that comes in various sizes:Link to product: Clear acrylic boxI wouldn't think it'd need to be anything too fancy or expensive.  

I also read in David Greene's BRRRR book that he likes to use rentometer.comWhat do you guys think?

Have you picked up David Greene's BRRRR book? 

@Jonathan Greene I completely agree with you!

Forgot to get a "before" pic of the bathroom, but here is the final product.

@blaine Moore - I'm a big fan of it, bought it on a Black Friday sale and I've noticed a large improvement in my productivity in the last 2 months.

With institutions entering the industry a few years back, more products have become available to us as lenders, resulting in better products to the borrowers.