There are some good opportunities in the San Ramon area. Most of the Windemere prices are over $600K and the property taxes in Windemere are 1.75%. HOA is going to run you between $100-$300 per month depending on the property.
As long as you can provide verification of you income and assets, you should be able to take advantage of the new Jumbo-Conforming loans, which in our area (Contra Costa as well as Alameda) is at $729,750. Most of the banks will go to 85% CLTV, therefore, you would have to come up with at least 15% of a downpayment. If you are planning on putting $100K as your downpayment, then you would be looking at a purchase price of around $665K. Without knowing your full financial situation, I have to make a number of assumptions about your credit score (which you state is excellent), and Debt-To-Income (which should be no more than 45%). Given today's rates, you would be looking between 6%- 6.5% for a 30-Year Fixed loan as well as 2-3 upfront points that some banks charge as part of the new Jumbo-Conforming program.
Have you thought about Dublin? Regarding rent, I have some investment properties and also help with property management. For example, my 2br/2ba condo in Dublin (1500 sq.ft.) is rented out for $2,100/month. A 4br/3ba SFH in San Ramon (2,300 sq.ft.) has just been rented out for $3,450. Rent is pretty strong in this area.
I would be happy to help you crunch some numbers and point you in the right direction. Please feel free to e-mail me at firstname.lastname@example.org