Now 10 years later my home is UP TO about $500,000 in value and therefore I am still far under water.  

Search through tools at the top and you can get there.https://www.biggerpockets.com/files/user/logdog/file/fha-self-sufficiency-rule-for-3--and-4-unit-properties

Mine has increased in value by 75%+ but that was in the fallout of the financial crisis.

Any one have tools or recommendations on how to best achieve this? 

So all together with a few personal holdings we are now sitting at 73 rental units and approximately 4.5 mil in valued assets.

if you do not have experience with building in your tool box.. most lenders will want a very experienced GC in the picture.. and MOST HML will not do verticle.

(Im not saying you pay the overhead, i.e. lifts, tools, compressor, whatever.)  

So in valuing apartment, instead of taking price/sqft of recently sold apartments and multiply it by the sqft of the apartment you're interested in, you would take the cap rate of the recently sold apartments and divide it into the NOI of the apartment you're interested in to calculate the value (i.e. offer price).

10 years will fly by and you'll be so glad you have acquired say 5 quality newer, always rented properties that should have almost doubled in value.  

I know an investor who has properties in Pittsburgh who has shared invaluable info with me about the areas and markets there.