Our blocks are created using a multitude of layers. Our colors and linetypes set to bylayer, since we need to show different linetypes and lineweights within one block, but do not have a need to turn off the layers that make up that block. All of our blocks are inserted on 0 layer.
Wow, that's completely backwards of the usual...
I can see how it might work, though. One of the things that i've often wished for is the ability to set a "lineweight factor" for an object. For example, a line inside a block could have its lineweight property set to "ByBlock", but with a Lineweight Factor of .5. This would cause that particular line to be half as thick as the lineweight of the overall block. It would acheive the same basic effect as what you're doing, but the blocks could be all on one layer. Best of both worlds.
Anyone noticed that 2007 products have problems with ByBlock and Named Plot Styles? If you use Named Plot Styles, you can't set Plot Style to be "ByBlock" - it doesn't work. I don't think setting lineweight to "ByBlock" works either - or at least, it doesn't always work, and I haven't quite figured out why it does or doesn't work. All of this worked fine before 2007.
