Sorry to have been so general in my post. Yes, indeed, you can do what you are wanting to do. The concept behind the tutorial and what you're referring to is really the same thing. ...however, I'm not sure if the tutorial is really answering your question, and I apologize for not being more thorough earlier.
I just had an idea. Instead of trying to be precise in photo shop, something I don't really know how to do, it would be easier perhaps to build the mesh you are trying to effect with texturing and then texture it and take a render of it from a 90 degree angle then lay that image over the simpler mesh. Know what I mean? Like when you are trying to do a design on a door (I have trouble with that kind of stuff).
Yes you can do this the way you describe it, and yes, you can do it by using the same principle as the tutorial. The concept really is the same. In Blender, under Bake is an option to bake a texture. Now, you can go about this in different ways with various results.
For example, you can choose one of Blender's built-in textures. Then, modify it's settings/colors to match the type of texture you want to create. At this point, you'd create a new image in UV/Image Editor (just like with lightmaps). Make it the size you want, then Bake. "No, this is not a tutorial..., and there are more steps:)"
You then save the image, reopen it in UV/Image Editor - and open it as the texture you want to use in the Edit Panel. Set it as UV and Col/Nor like any other texture.
Of course, there's a plethora of things you can do from this point. (Sorry, I don't want to over-complicate this.)
If you're skinning an object (which I'm assuming you are), you can a lot with the Normal/Bump maps that Blender can create for you. Although you can't implement this stuff in URU yet, you can fake it with a really good texture. By starting with your base texture made in Blender, you can then add fancy lighting (and the Bump/Normal maps) by using Gimp/Photoshop to add an Alpha Channel to them. Then, merge them with the base image. At this point, you could load the merged image back up in Blender as the object's texture. Go into Texture Paint and add more details. Save the image, then go back into Photoshop/Gimp to touch it up.
I can see you have experience dealing with image editors. By combining your experience with Blender's Bake and Texture abilities, you can do some cool stuff.

P.S. Yes, you'll still have to use Photoshop or some other editor in conjunction with Blender.
