I have been a designer for several years with a great interest in typography, but my experience is almost entirely with using existing typefaces... i.e. I have no experience drawing my own letterforms. Over the last couple of years I've become more and more interested in the work of Herb Lubalin, Tom Carnase, and Tony Di Spigna. What I'm particularly interested in learning is hand lettering / custom-designing typographic compositions for the purposes of logo design and individual type treatments (like the images I'm posting below), rather than designing entire typefaces.
I've done a fair amount of research on this kind of custom lettering (i.e. I've found tons of examples, which are really inspiring), but I have no idea where to start to learn something like this. I'm quite comfortable in Adobe Illustrator, but I have no tools or knowledge about actual hand lettering with tools like pen and ink.
I have some resources I could devote to this, in terms of taking classes, buying books, equipment, etc. but I don't know how to go about it. Does anyone still teach this kind of thing? Should I start with calligraphy?
If anyone has any guidance or suggestions, I'd be very appreciative.
(Also, if you think this would be ridiculously difficult to learn, tell me.)