No way to do it in Safari.
The Atomic web browser is fairly cheap (99 cents), and will let you view the page source. There is a free, lite, version as well. I don't know if that feature is included, but probably. So you can test it and see if it's what you need.
All you need to do is copy the URL when you see a page you are interested in and then paste it into Atomic.
As a bonus, Atomic can change it's browser ID. That means website can be fooled into thinking that it is a desktop browser. Useful for when you want to bypass a mobile site that offers no link to the desktop version. Hold in mind that the desktop version may not work well, which is the normal reason to not offer the site, but in your case you may want to be able to see it and see the source anyway.
I'm sure there are other third party browsers that will view the source; however, it is the only one I have that does it, or does it easily enough that I did not need to dig into settings to find the option.