Searching "monograms" might lead to some good stuff. I haven't seen it directly but I have a feeling this book would be exactly what you need. There's a spread from the book reproduced at this blog.

The most famous of these could be the logo for the Montreal Canadiens hockey team.

eliason- 1) I'm gonna get that book (found it on amazon) 2) The Yankees mark didn't even cross my mind!

riccard0- Edited to wide and narrow, thank you! Those are some great links (though the two links under 'Two examples' are blocked or something) - it's really unfortunate that the Italian banks are being grouped together and losing their old identities :(

Don McCahill- Ballin

Summary so far:

The mark above with the 'wide and narrow' combination is better described as a monogram than a logo-
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Some great examples:

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contemporary spin:

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so familiar I didn't even think of them:

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So what else is cool from this time period that has a similar feel?

the two links under 'Two examples' are blocked or something

Here they are:

Here's a fun little book with a bunch of fanciful things like that.

Nick, you are blessed with eminently weavable initials! (You should make a baseball cap!)

I know! I love the internet archive for old obscure resources! It's especially nice if you happen to live in a rural area without reasonable access to any sort of nice library (I don't anymore, but used to).

The "read online" versions tend to be zoomable to much higher resolutions than the .pdf versions, by the way, but they're annoying to read unless you have pretty decent and consistent bandwidth.

I don't remember what that broken link was supposed to go to, but I'm sure it's amongst those listed in the second link anyway.