Is it possible to replace the dock (but just the dock)? I have a HTC Desire HD and I like Sense (and the apps provided by HTC) a lot. But I really hate the default launcher (specifically the dock).

The problem is that if I change my launcher, I will lose the ability to use HTC Sense widgets. Is it possible to replace just the dock, but leave the rest of the launcher intact?
Unfortunately, No. The "dock" is part of the entire launcher and "home screens". They are, all the "same application". But there are widgets like most of the widgets that HTC Sense has. If you really don't like it that much, you should be able to find replacement widgets for the ones you like that work with other launchers like Launcher Pro, GO Launcher, or ADW Launcher, for example.