Okay, I found a decent, but not perfect solution.
1) Download MoreLocale 2 from Google Play.
2) Open it, press the menu button, and select "Add Locale"
3) Label it any name you want. For language, keep "en", but for country, use United Kingdom (code "GB")
4) Enable the new locale you created.
5) For every new contact you create, make sure you add a 1 (if it's a US number) to the beginning of each number.
Now, for contacts you already have in your phone:
1) Download and install "Android Contacts Cleanup"
android-contacts-cleanup - A utility for cleaning-up contact data - Google Project Hosting
2) Input your country code and area code, and select the fourth format.
3) Let it redo all of your contacts.
If anyone has an idea how I can get texting to work in the preferred US number format, (xxx) xxx-xxxx, please let me know.