As I have told someone else who's interested in the area you're looking at, the stronger you are as a buyer, the more likely the production home builder will negotiate with you. The fact is qualified buyers are rare these days, inventory is still high, and production home builders like Lennar and Toll have every intention of attracting home buyers with solid finances whose loan won't fall through at the last minute. Always bring prices from comparable floorplans from other developments in you negotiation. Also, consider getting Lennar to agree to a price guarantee until built out, which similar to the one being offered by Shea Homes at their Montage project in Livermore. There is absolutely no need to rush things.
East Dubin is centrally located and beautifully landscaped. We have a fantastic middle school and a few great elementary schools, but we are far away from the high school. To learn more about this area (upcoming residential developments like Wallis Ranch and Fallon Village and upcoming retail development like the Promenade and Grafton Station), I highly recommend the blog referenced below. Every Friday, this blog will graphically summarize the week's Dublin home sales data from Pleasanton Weekly for its readers. These data should be helpful in your negotiation. Good luck on your search.