I had looked at those 3rd party docs a bit, but they're super expensive, like triple what a dock for a Lenovo T500 would be. And to me a lot of the point is to save the ports from breaking by unplugging/replugging a few times a day, especially the mini-DVI port, we've had a few users that have gone through them, and I think mine is starting to be a problem. I'm not sure my company would go for it, but I can hope.
The "support not scaling" came from a friend who worked at a large, mostly Mac, multi-location company that we've all heard of and use. His problem was that if one of their laptops died, he'd have to call customer service, who'd tell him to take it to an Apple store, he'd say "no, here's what's going to happen, you're going to send me an empty box with a shipping label on it, I'm going to send the machine back to you, then later, you'll send it back fixed". They'd do it, but it was a hassle. Again this was a few years ago, and I seem to recall that they were working on Corporate Support as an initiative at some point recently. Maybe they fixed it. We usually deal with resellers, so if something breaks, send it back to the reseller and have them deal with it. Still, it's nothing like HP enterprise support, log into site, generate ticket, problem gets fixed (at least for server products, I have no experience with HP in the desktop/laptop space).