@Rich Thomas started out as a client and ended up as a friend!

Is he an investor himself or does he have lots of clients who own real estate?

That being said, they do serve their purpose especially with higher $$$ amounts or # of properties > 20, but much of the time I find that for different reasons, @Andrew Kerr is correct, it is worth the "headache" of doing 10 individual loans.  

That could serve as a POF, for say a downpayment amount.  

My rehab clients source from wholesalers or their network - after you get a reputation for flipping a couple, deals will get brought to you all the time. 

Myself I am prior Navy, served with Special Boat Units....now referred to as SWCC.I'd be curious to know what the answers are to your questions as well.

I have had clients come up with all sorts of stuff days after closing and my answer has always been the same.

I also feel that the knowledge I gain from doing investing benefits my buyer/seller clients.

My PM has advised me that they have a different client who has successfully fought the appraisal, but it took about 3 years, and probably cost a fortune in legal fees. 

@Justin Feldstein this is primarily what we do for our clients.