Not quite as personalized as Lynda Wallenfells probably, but WAY more affordable, and high cred! - http://www.alisondunlapcoaching.com/

I've also used the road bike century training program from this book, which includes "weekend warrior" MTB plans as well as an MTB racing plan. I'm about to start one of her foundation plans...there are a lot of different kinds of intervals and speed/cadence/technique exercises that you could use even without getting totally into the plans.