Why reinvent the wheel? Here are some sample Request for Proposals and other implementing documents.
The Local Government Commission has posted some sample Request for Proposals for solar installations. San Francisco recently issued a RFP for a 250 kW system on the South East Water Pollution Control Plant (PDF).
Another strategy is to select the most qualified photovoltaic installer through a Request for Qualifications (Word/.zip) procedure, then utilize their expertise to jointly develop the best projects.
Instead of buying solar systems, why not buy solar electricity? This method also allows municipalities, which don't have tax burdens, to utilize the 30% federal tax credit. The City of San Diego recently signed a 5 MW deal (PDF) below utility rates. We've posted the RFP (PDF) and related documents exhibit A (PDF) and exhibits B-G (PDF).
Check back soon — we are in the process of developing some model documents.