Determining neighborhood value without comps

[Matthew Augustine]

Bear with me here for a minute and i'll explain. A small desirable town, inventory has been little to none for almost three years running. The town itself however, has undergone and continues to undergo large scale "building up" if you will. New roads, new parks, everyone adding whole levels onto their house or completely renovating properties (to hold, not to sell) 

Obviously these things do not reflect in sold homes value - what little has been sold has been sold very high, but they are typically retirement age people and those houses aren't reflective of the neighborhood as a whole. There has to be some inherent value to the fact that everyone is rehabbing, expanding, and holding on to their properties and the infrastructure of the town itself has undergone massive upgrading. How do you determine this, however? If attempting say, a flip in such an area, what numbers would you use? How would you define values?