Brian,
That will (apparently) depend on where the integrator is located in the world.
Over the past two years my company has been working with a manufacturer that deals extensively in emerging markets. When we were trying to figure out how we were going to work together they kept telling us that North American integrators are too rigid. For example, we evaluated their product and come back to them with a number of "must haves" and some "nice to haves" for their product if it was going to succeed in the NA market and we were told that they offer an SDK and that we should implement whatever we wanted to better sell the product. When we explained that we do not do custom development work for our customers because of the liability / support reasons raised here, we were told that we are at risk of being made obsolete by a new breed of Value Added Reseller / Integrators.
Apparently in the EMEA and BRIC countries the "good" integrators are one stop shops that create and develop "solutions" themselves. These integrators purchase stock, develop custom solutions and self warranty product - all in an effort to get better margins on products. They can apparently turn on a dime and build exactly what the customer needs, and not rely on a manufacturer to build it out.
Now, this may work in those regions but I do not know of any shop in NA that could run a successful integration business with this model. Inevitably the service / installation side of the business would be propping up the development / support side. In NA the cost of labour is simply too high for this type of business model to work IMHO.
In the few business that I have seen go down this road, they put all of their eggs in one basket - i.e. a "senior" developer that can architect the software / solution. They will then hire cheaper talent (typically off-shore) to write the majority of the code. The issue then becomes when that person leaves (better money somewhere else, god complex develops, etc) the integrator is left in the lurch trying to support a piece of software he likely has little knowledge of and little to no documentation on.
I wholeheartedly agree that it is one thing for IT integrators to add another IP based widget to their network - it is quite another for a service business to start full stack development.