"What I should have said and was in too much of a hurry, was that an sRGB monitor can't really soft proof because the display gamut is smaller than a lot of printers or at least doesn't contain some printer colors in the case of ink jets."
On the surface, that sounds well and good but in practice, soft proofing works very very well with an sRGB-ish display. It really does. I've made thousands of print over the last decade on large formate Epson's and soft proofed them all on a lowly Sony Artisan. Every once in a while there'd be a surprise, but not where you expect. I specifically remember printing an image for Honeywell that had factory workers in standard issue blue smocks. The files (sRGB btw) looked perfect on the Artisan, but the first print, printed through my own custom paper profile, rendered those blue smocks way too saturated. sRGB file. sRGB monitor, and an Epson 9900 printer using Lexjet eSatin, which is the equivalent of Epson Premium Luster. Now that was a surprise. I dropped the saturation of the blues and reprinted. Perfect. But, by and large with many thousands of images, they just printed right and we moved on to the next. Not a big deal.
Now, with a new Eizo CG277, which has ninety-nine percent of Adobe RGB, the results are basically the same. Yes, there are some brighter colors on the Eizo but for most images, it just doesn't matter, and when it does matter it's never as huge a deal as so many here would have you believe.
"I'm not sure what the display's rendering intent does either. I have read that monitors use perceptual. I think that would depend on the manufacturer and/or the display profiler app."
No, the monitors, as far as I know all use Relative to go from working RGB to the monitor profile. As I said earlier, it wouldn't make any sense to use anything else. It's not "up" to the monitor manufacturer. It's up to the color management system, and the imaging application you are using. A display doesn't have a rendering intent itself, only the system of profiles - Source and Destination - that are in place to display your images.
And to further emphasize this, you need to go no further than the advanced panel in the Color Settings dialog and look to the "Desaturate By ___ Percent" option for you display. That option, which virtually no one ever uses and even fewer actually know about, was put there to simulate the effect of a Perceptual rendering intent on you monitor. And it does indeed work. Take a saturated ProPhoto RGB file with super saturated color with detail (you can measure the detail you can't see using the Info Palette - if the numbers move around as you move the cursor, you know there's color differentiation even when it's invisible on screen), then put in a number - say thirty percent or so, and magically, you'll be able to see the gradations in you file that were once completely hidden. Of course, the overall color accuracy will be compromised. It's a cool feature but it's not very practical on a day to day basis. But now you know about it.
"I think that an aRGB monitor would provide a much better, but still not totally accurate soft proof, but what do I care, I'll never use it un;ess I decide to check a print after the fact."
Yes, in theory you're right, the wider gamut monitor will be more accurate, but only in the areas and in images that actually have larger than sRGB color data.
"I go from RAW to ProPhoto to manages colors to perceptual for my prints, so when I do it now with a wide gamut display I'll get more colors in gamut and be pretty, oh so pretty, lala la lala la la."
Well, maybe. It all depends on your exact workflow and how you handle your files. It's all too easy to push your files too far in ProPhoto, particularly if you aren't paying close attention to the numbers as you manipulate your image. Perceptual rendering is always a compromise and it's not always the best compromise. If you're using a wider-ish gamut inkjet paper with a gloss or semi-gloss paper, you might actually like Relative Colorimetric rendering, especially when you're dealing with most "ordinary" images - those without super saturated flowers and the like.