What does it mean to be a Service Delivery Manager?

Over the past 2 years I've been thinking that we could really use a Service Delivery Manager where I work. Curiously enough, it turns out that the new Technical Operations Manager thinks so as well and sees the role as fundamental to contributing to the overall strategy for service provision. So he asked me to write a paper outlining my strategy for service provision over the coming years. Great, except that as the reporting lines have not yet been resolved my line managers are reluctant to let me spend any time researching and writing the report as it will take away from the day job. A fair point, but should I really be doing this in my own time and not being paid for it? Part of me says 'no' - it is for work to benefit therefore I should continue to maintain my work/life balance. Another part says that it is a missed opportunity for me personally if I do not.

Anyhow... all of this has me wondering 'What does it mean to be a Service Delivery Manager?' I believe it is more than service level management as defined by ITIL, and it should include service introduction management. I'd like to write a job description and person specification, so, as a starting point, started trawling job adverts only to find there is a wide range of views. Over the next week or so I'm throwing the question open to the rest of you. I'll write up my answer in a couple of weeks incorporating your views, and although it may not be definitive - hopefully it will be a reasonable answer to an important question.