I'm reviewing a $2.5MM flooring line of credit to a manufactured home builder/dealer located in a moderate tract, in an area where affordable housing is a significant issue. What kind of documentation would I need to qualify this as an affordable housing loan for CD credit?

You might need to know where the mobile homes actually end up.

What are the qualifying CD possibilities? It could be affordable housing if you have a way of documenting the housing is affordable and the beneficiaries are low- or moderate-income tenants. For this to apply it doesn't matter where the company is located. It's totally dependent on the affordability of the housing and the qualifications of the beneficiaries. Don't forget too, that the affordable housing should be within your Assessment Area or within an area that includes your AA for it to count toward a "satisfactory" CD rating. The company is located in your AA, but is the housing located there too? BTW, don't forget that the only CD definition that depends on the tract income class is the revitalization/stabilization definition.

You might be able to claim CD credit under the revitalization/stabilization definition if you can establish that you are financing an activity that "attracts or retains people or businesses" to the moderate-income tract. It's not a sure-fire bet, but it may be worth claiming. The last I heard they don't hang CRA officers for a good faith effort to capture all CRA-related activity.