Funds & Grants for wheelchair-modified vehicles
https://www.braunability.com/help-me-buy/financing/#grants-funds

Access Paratransit - Santa Clara County & Interactive Paratransit Site
http://www.vta.org/getting-around/paratransit/accessibility-paratransit-service

Metropolitan Transportation Commission for the Bay Area
https://mtc.ca.gov/our-work/plans-projects/other-plans/coordinated-public-transit-human-services-transportation-plan

Public transportation options by county for the San Francisco Bay Area
Alameda
http://accessalameda.com/

Contra Costa
http://www.mobilitymatterscc.com/

Marin
http://marinaccess.org/

Napa
http://www.ridethevine.com/ada-accessibility-0

San Francisco
http://www.sfparatransit.com/general-info.htm

San Mateo
http://www.samtrans.com/Accessibility/Paratransit.html

Santa Clara
http://www.vta.org/getting-around/paratransit/accessibility

Solano
http://www.solanomobility.org/

Sonoma
http://www.sonomaaccess.org/Home.aspx

Department of Rehabilitation Mobility Evaluation Program
http://www.rehab.cahwnet.gov/MEP

The National Mobility Equipment Dealers Association (NMEDA) is a non-profit trade association dedicated to expanding opportunities for people with disabilities to safely drive or be transported in vehicles modified with mobility equipment to fit their specific needs.
http://www.nmeda.com/

For-profit companies specializing in vehicle modifications for individuals with a physical disability
Ability Center:
http://www.abilitycenter.com/
Access Options:  
http://www.accessoptions.com/
Lifestyle Mobility: http://www.lifestylemobility.com/
Mobility Systems:  http://mobilitysystems.com/
Mobility Works:  https://www.mobilityworks.com/
Modesto Mobility Center:
http://modestomobilitycenter.com/
Sacramento Van Conversions & Mobility: https://sacvans.com/