Using Waterfall and SCRUM together?

Can it possible to even think of the idea that Waterfall and SCRUM can me combined? Well, I was talking to a CTO of an established company, 350 employees, 70 million dollar run rate-- they have over 100 engineers and established product and they just moved to SCRUM about a year ago. It was an interesting conversation and I would love to get opinions on this as I have some of my own.

Here are some snippets from the conversation...
- Waterfall is a great way to communicate releases and dates
- Scrum can do the same but its a continuous process with no seeming end-date ( at least thats how some people perceive it)
- Execs are used to Waterfall where concepts of GA releases have a ship date

In a recent project at Oracle I was able to use the strengths of both approaches in helping deliver software. I am curious if there are others sharing similar or different thoughts on this. One could argue that if we needed both then perhaps SCRUM wasn't followed that strictly since one can group stories and backlog items into a release.

comments welcome..