One wonderful property I have that's forty minutes away from where I wake up every morning is at the outer limit of my 'zone.

As far as proof of funds, do you have a high credit card limit?  

Being a realtor has limitations as all transaction are regarded as regular income (add both side is SS and regular tax rate  25 percent, instead of long term capital gains15 percent) so for me it’s the difference of 23 percent taxes versus 46 percent.

Do I form a limited partnership with an agreement specifying these details?

However, certain issues, such as limited partnership interests are always presumed to be securities. 

Other than coming up with 20%+ down on the full amount, how could owner financing play into this situation to limit the amount of capital required upfront?

If this is the case after a title search just get them to sign a general or limited warranty deed.

You do have to recapture what your were entitled to take in depreciation (whether you did or not) and that is taxed at ordinary income with a limit of 25%

Is there a limit on the number of loans on a property?

Limit the amount of time needed for showings, i.e. 2 hours vs. an all-day event.