I'd add a couple of things. Some of the simpler meters/circuits are such that they really shouldn't be left in line (lots of power loss, heating, etc) yet others can be left in line constantly. That may or may not matter to you. As Nigel says, cost is low on some models and it's not cost effective for you to duplicate one of those.
One feature that you might find useful - the ability to locate the meter separately from the measurement bridge. I am working on meters for my shack where the meter can be a few feet or more from the bridge/sensing portion. It seems that those models are costly enough that duplication might save you some money. The advantage - you can put the meter where it works for you and not have to run coax all over the place.
Note that FAR Circuits has etched PCBs for many of the projects you'd find in the publications mentioned.
If you do decide to homebrew your own don't get too concerned about the meter scale. It's likley that you'll only be interested in relative readings - maybe you'll want to memorize where the 2:1 or 3:1 point is but beyond that you may not need to do much with the scale. Note also that there are a number of audio, digital or PIC based projects that have been well documented.