DNS is so easy, I would just do it myself. Once you figure out a single zone then just use as a template for any other zone. One zone per domain.
We use DNS Made Easy. Love, love, love the service. We use it primarily for the DNS and server monitoring (A record failover) aspects. Prices are very affordable and their feature sets and performance match the other providers that are much more expensive (read: Dyn).
We have the business plan which is $60/yr, provides up to 25 domains (can purchase more if needed) and up to 10m queries per month.