(The icon on the left is suited for 16x16 size. The icon in right is the same icon, just suited for larger scales)
I think this scheme is supported by FreeDesktop.org's Icon Theme Specifications and other icon theme's used on Linux desktops (like Tango) use the same scheme.
Indeed, in that they have multiple SVG versions of the same icon (name) for smaller pixel sizes - 16x16, 22x22, 24x24, 32x32 - the last time I checked.
That seems like the appropriate compromise, SVG for various optical sizes. The analog example that comes to mind is Dr. Seuss books. The Cat in the Hat is much less detailed when he is far away, and has very detailed pen work close up.
http://wstaw.org/m/2012/03/18/plasma-desktopA20554.png
(The icon on the left is suited for 16x16 size. The icon in right is the same icon, just suited for larger scales)
I think this scheme is supported by FreeDesktop.org's Icon Theme Specifications and other icon theme's used on Linux desktops (like Tango) use the same scheme.