My website isn't even up yet, but here is what I am working on as far as niches, but plan to offer more generalized support in other areas

Construction contractors support
Materials and services pricing and inventory analysis (aka shopping around )
Statute and regulation research
Document preparation including, but not limited to, bid proposals and lien claims
Subcontractor background checks
Project planning/time management support

Customer Relations consultant
Plan and establish CR procedures and policies for new businesses
Analyze and suggest improvements for existing CR systems
Analyze marketing and sales materials from a CR standpoint