Just some thoughts on this....... how would you seperate yourself from your firm? I also wonder with all the cad packages around why designers don't included details in their drawings? All the major paver and wall suppliers give them away. Tree and shrub planting details are easy to come by along with most specifaction on proper installing. Most drawing might need one extra sheet for details and 5 or 6 pages of specs.
Now is this do able for home owners? Having not work with them in over 10 years I don't know.