I've been attempting to reach the owners of vacant/distressed homes but haven't had any luck yet with any skip tracing services.

Yes for total investment include all your costs this is your total cash outlay most investors skip this step and or underestimate completely to juice their numbers.This could go on and on but hope this helps a littleJon Bock, CPA 

As mentioned: skip the LLC and just buy a decent umbrella policy.

What does everyone do when the skip trace brings up the wrong numbers or no numbers at all?

Yes, be strict in screening, but if you have too much upfront (you and I both know) that everyone will just skip the process and move onto the next place.

@Mike Sullivan, I think @Greg M. and @Andrew B. skipped step #1.

I wouldn't give much more then you need to otherwise they might skip out in payment. 

Have pricing and packages listed in detail, I remember when I needed a photographer in the past I went to craigslist and viewed a few sites, and the ones that didn't have their services detailed, I skipped.

Tenants are often times very nervous taking over an apartment, and that first lease signing is tough to skip I find. 

As its been posted on BP many times, you could skip the LLC route.