good DVI cable info needed for in-wall cable planning

I am planning a home office makeover for which I will be putting my PC, cable modem, and router-and a new Tivo, receiver, and NAS drive-into a closet right next to my stand-up desk; using the closet is to reduce the visual clutter and noise. All my cables will be snaked through the wall by a professional AV installer, with wall plates for all connections. I will be getting a new 24” LCD monitor (1920x1200) mounted on the wall behind my desk, with all cables for it hidden as well, but think I will upgrade to a 30” Gateway FHD 3000 (2560x1600) in a year or two.

With this context, and my lack of hardware knowledge, my question concerns the DVI cable that will have to go into the wall. Obviously, I don’t want to have to tear into the wall again in a year or two to replace the DVI cable. Since the 30” monitor requires a “dual link” DVI cable but the 24” one does not, I’d like to understand what I need to get right in planning for this cable and the connectors/wall plates I get installed. Questions about these DVI issues I have but have not been able to get answered by PC stores, Google searches, AV installers, or in Wikipedia include:

• What does a dual-link cable require? Is it 2 cables in one?
• Are any DVI cables hand-wired by PC enthusiasts, or does everyone just buy them manufactured that way?
• Is the DVI connector on a monitor always a female one?
• Can a dual link female connector accept a single link male connector, if they are both the same type (DVI-I or DVI-D)?
• If a monitor supports the larger 2560x1600 resolution and requires dual link DVI, is the connector on the monitor a DVI-D or a DVI-I one, or does it depend on the manufacturer?
• If my initial 24” monitor only has a DVI-D or DVI-I single link connector on it, how do I upgrade the DVI cable in my wall to a dual link connector when I get the 30” monitor?
• Are there adapters to convert ALL DVI connector types to ones of the other type?

Datapro.net, referenced in other postings in this forum, seems to have good DVI information, but I still have these questions. That’s probably not the complete set of questions, but if you understand the issues and can answer all my questions, you probably know ALL the info I need, even if I don’t know which questions I have forgotten to ask. So I would appreciate your help.