I hope you won't mind if i clarify a few things as I think a few of the points are a little unclear.
"CMYK and RGB are different gamuts." - No. CMYK are colourants. When you work in Adobe CS you work in a specific CMYK colour space (default is US Web Coated SWOP, but FOGRA39 is more common now). Those colour spaces represent different things. US Web Coated SWOP represents all of the colours that can be reproduced using SWOP certified inks on a litho press, on a particular stock, with a certain dot gain, with etc etc... The "Gamut" of US Web COated SWOP means the range of colours in that particular colour space - the range of colours that a press can produce with those inks on that media.
The same applies to RGB. RGB are illuminants. Standard working space in Adobe is sRGB - an imaginary colour space designed to represent the average colour capabilities of an internet viewing monitor. AdobeRGB is just a different RGB colour space using different illuminants... NikonRGB represents all of the colours registered by the sensor on a Nikon etc etc the same theory applies as with CMYK above.
When you're designing, it doesn't matter which you work in, provided you understand what these things stand for. Define a colour as four percentages or three percentages, makes no difference at all. But you must know "PERCENTAGES OF WHAT" If you answer that "percentages of CMYK" then the next question is "WHICH CMYK?" Imagine asking a paint store to mix 20% blue paint with 30% yellow paint. Then going into another paint store, doing the same thing. Unless you specify which specific brand and shade of blue and yellow you're meaning, you'll get the right mix, but completely different colours. It's all numbers, and if you don't understand what those numbers represent, or what is happening when you convert from one definition to another, you'll lose control of your colour.
"RGB has a wider gamut than CMYK. Thusly, CMYK has a narrower range in gamut." True most of the time in standard colour spaces, but not necessarily so. It's just numbers. There are small RGB spaces and large CMYK spaces.
Try this article about colour spaces
Colour Spaces | Hudson
"CMYK can never ever ever replicate correctly in RGB - it simply won't happen." - I've got several softproofing monitors here that show me exactly what's about to come out of my printer that prove that wrong.
"Wheras, if your logo is in RGB then converting it to CMYK is easier as RGB has a wider gamut so your colours are more closely matched." Some confusion here I think. I think you mean the reverse. What I think you mean is - if you design in a small colour space then if you convert to a bigger space all of your colours can remain the same, whereas if you design in a large space and then need to convert to a smaller space you'll end up changing your colour.
"Pantone is a limited range of colours (gamut) that cannot be reproduced with CMYK or RGB." Now you've lost me. Pantone is an extensive range of colours, nearly all of which can be produced by an AdobeRGB capable monitor, and 97% of which I can print on some media on some printers.
"Different output intents have different builds of CMYK or RGB." Please see my comment above re: colour spaces. You're using "builds" to mean colour spaces.
The first image in this article shows the same CMYK percentages in different colour spaces - effectively demonstrating what you're meaning. In different colour spaces, the same numbers give different colours -
RGB or CMYK? Colour Spaces - what should you work in? | Hudson
"converting plain CMYK to RGB is a crapshoot" Interestingly, there's no such thing as "plain CMYK". In Adobe CS, even if your document is showing as "untagged CMYK" you're working in your CMYK Working Space. If you're defining a colour as percentages, to see anything, you have to know percentages of what.
"because CMYK doesn't have the necessary gamut (range of colours) to replicate a RGB gamut." A lot of the time if you design in a large colour space like AdobeRGB and are printing on a SWOP press - what you're describing happens to be what you'll see. But this isn't an RGB vs CMYK spaces thing. For example, the gamut of my JV3 printing on a particular vinyl, exceeds the gamut of sRGB in most areas. Converting between sRGB and my CMYK profile for that product would lead to almost no loss of colour.
"Basically your CMYK will always be out of gamut with RGB - all the time." No, that's simply not true. If your design is in a large colour space and you convert to a smaller colour space some colours may be "out of gamut" ie. exist in the large space and don't exist in the small space. But a lot of the colours will exist in both gamuts, and converting those should lead to no change in colour. This article has some images in it you'll be interested in. It shows that the gamut of my JV3 printing on LD3811G vinyl can achieve colours outside of the gamut of AdobeRGB.
RGB or CMYK? The CMYK habit discussed! | Hudson
I'm sorry that I've picked at one of your posts here hankscorpio, it is not my intention to offend. I think some of what you were meaning was lost in what was written, and I hope I've helped rather than annoyed.
If designers understand what colour spaces are, knowing that they are using them like it or not, then they pay more attention to converting accurately between spaces. Adobe CS has gamut warnings and proofing options built in. You can see what will happen to your colours when you output or convert into different spaces... It's just numbers, and none of it is that complicated once you know what the terms really mean.
Your book recommendation was spot on. Fraser's work is the bible on this subject! Worth taking a look at the IDEAlliance Colour Management Professional Qualifications too if this is something you use on a daily basis.
