Well, first, there simply isn't that much. A sad, but unavoidable truth. Apart from Fucking Åmål, there are only four roles worthy of note: "Närkontakt" (short film), Adam & Eva (episodes 14-16), "Sherdil" (feature film, lead role) und "Bear's Kiss" (feature film, lead role). The rest of the stuff in her imdb list are just tiny, tiny parts (nearly cameos) and the Sunes's Jul series (when she was 9 years old).
"Närkontakt" can be downloaded completely from the net. All of Rebecka's scenes from "Adam & Eva" too. I guess you've done your research and know that. If not, find the links here:
http://www.goodwin.ee/vidcaps.html
http://membres.lycos.fr/smlfa/vari.html
Concerning "Sherdil" and "Bear's Kiss", they are available on DVD for sale, first from the webshop of the site we're on:
[url]http:///showmelove.org[/url]
What other options there are depends on where you are based?
In Germany, e.g., Bear's Kiss is available on DVD for rent and for sale (on ebay also), but not "Sherdil" (which I haven't seen). Both films have been shown on German TV and I hope they will show them again.
Besides however, it is widely accepted that "Bear's Kiss" and "Sherdil" as well are in fact pretty mediocre if not downright bad films. Apart from R., there is no reason to watch them. That alone makes her appearance in all of them less spectacular than in Fucking Åmål. Once you've seen them, it gets painfully clear just how great she is, but how much of her greatness in Fucking Åmål depended on the greatness of that film's script and direction and on the chemistry with Alexandra.