It happens all too often where people will buy a property together, and one partner says man this isn't what I expected, and the other is pedal to the metal ready to buy every piece of real estate he can get his hands on, and they don't know how to break up their operations or compensate someone who wants out. 

You might try https://www.mfssolutions.com/.I have not used them, but had their info in my contacts, so must have thought they were interesting at some point.Same for bulkwooddesign-cabinetry.com  in Dallas.Might also try Surplus Building Materials in Addison, but not sure they do bulk.There is someone in the multifamily community that also does bulk supplies...trying to think of who that is....they're really an operator, but do enough renovations they started a sideline business. 

Going to be difficult to solve a supply side (labor/oil/materials) problem with a demand side solution. 

The lynch pin that makes the STR loophole work is only needing 500 hours material participation (or 100 hours and more hours than anyone else) instead of full on REPS, as long as your average stay is less than seven days.

To be honest, prices for material and services change constantly and any book will be outdated as soon as it hits the streets.

Its not the material its the labor and insurance. 

Total renovation including all materials (except appliance) was $57,000.

One thing I am inclined to provide is good quality metal mesh water lines so they don't bring their crusty crappy dry rotted 15 year old water lines when they move in my unit and then wonder why they break and flood the unit.

Use only quality 3m or equilivent film material.

Materials ran a little higher than planned.