I think the problem shows how difficult it is to separate content from presentation, and make it medium-independent (suitable for different screensizes, skins, or even devices). We’ll have to stick to very simple formats per rss item: some text with 1 image, audio file or movie, or with a combination of audio and a picture at maximum.

But also: avoid adding presentational markup in the html… If you add “width: 400px” to make it suitable for Blogger, than you ask from other presentational layers to strip that 400px again… whereas the 400px rule should be in the presentation layer that is Blogger, not in your content. Maybe you can try something like

.post-body img {
padding: 0;
max-width: 100%;
}

in your css file?

BTW: Luc has a point about the lack of internal structure of RSS, SMIL was created for multimedia presentations.

But then again, Smil didn’t succeed, and wizaRSS could piggyback on the popularity of RSS+enclosures (which it is) to get some popularity.

With a simple combination of RSS and video enclosures + a javascript + html skin like S5, it should be possible to achieve something (maybe not as smooth and fully automated, but still) like microsoft producer 2003 for which you need a Powerpoint plugin to produce and an extra ActiveX control to display…