We currently have policies for each place, which have minimal interior coverage, and 100k of liability per policy.

A default policy will often exclude mechanics' liens but you should be able to get that clause removed.Some title companies will request the seller to provide lien waivers for all work performed over a certain dollar value in the last few months.

I just PMed you a guy that has wrote a few builders risk policies for us in the past. 

If you want to mitigate risk, I would get an umbrella insurance policy.

Get a 1 or 2 million dollar policy and you'll be fine.

I have put $300k liability insurance on each of my rentals and have a million dollar umbrella policy covering them and my personal home and cars as well.  

One thing to consider is most E&O insurance policies do not cover you if you are a principle to the transaction.

Both the Nationwide agent who sold me the policy -- Terrence Gannon -- and every other agent I spoke to before accepting Gannon's bid came up with the same number, which is close to the $125 per square foot average for Philly row houses.

When I bought the policy I was not given any choice between replacement value and market value. 

Late rent policies must be consistently applied to all tenants.