San Ramon's been booming for years. Now it's bracing for a possible influx of more than 100,000 bodies. Dead ones, that is. Contra Costa County's planning commission is expected to decide this fall on a developer's plan to build a 220-acre cemetery in a rugged, agricultural patch of Tassajara Valley. The developer says the cemetery is badly needed to accommodate the ever-increasing Tri-Valley population, while opponents say it's a water-hogging development in one of the driest parts of the Bay Area and is culturally insensitive, to boot.