[notJim]

+1 on feature flags. Set up your flags so you can disable features for certain customers, or groups/classes of customers. Delivery and release can then be separated. Release frequently, deliver features when it makes sense.

Also recommend making sure customers know that this is time-limited, otherwise you end up supporting too many different configurations of your product.

Also if these are customers you're in regular contact with, you can preview your roadmap or demo features that are coming soon. This helps them feel in the loop, and gives them a chance to provide feedback.