How do you know how much you should spend on, say, 30 minutes of eLearning and how can you sensibly define a budget.

What are your views?

I think that budget tends to be set in blocks of higher or lower investment and that helps set the initial framework, but the real issues is how you engage your learner and how you make the level of the content match their needs and expectations.
Any bench marks out there?

"how you engage your learner and how you make the level of the content match their needs and expectations."

Good question. It may seem obvious but you should start defining what their needs and expectations are. You can use surveys or interviews to define these - althoug I would favor something like a web 2.0 application that allows learners to update their needs on a continuous basis. Once the needs are well-defined, you have to examine how your learning offerings are aligned with these needs and go after the low-hangng fruits.

I am curious to hear what other ideas you gather on this question.

Me too Micheal. I tend to agree: meet the needs in the best way possible but keep the threads loose so content can evolve and the be incorporated into the dialogue. It is then much easier to argue for complexity and bigger investment if it is needed because that is the exception rather than the rule.