One huge problem with that theory is that she has family and memories that place her growing up in Baerlon. So that's not possible. I think we have to just accept that no character in play, except some of the darkspawn have any possibility of being finns. It's remotely possible that Shaidar Haran is made from a finn instead of a Trolloc.
Ahh, sorry, I didn't make it clear, but I don't think the theory was ever really a true theory. The author didn't seem to really believe it (and I didn't), but it was very well put together, and I kind of wish it were true.
I will point out that the only family she seems to remember/talk about are three "aunts".
I remember reading it on Wotmania, so I went and used the internet's wayback machine to try and find it (wotmania closed down about 8 months ago). I found this one, but I seem to remember another one. The comments kind of flesh out the idea a bit, maybe my mind built up its awesomeness since it's been a while since I last read it.
Anyways, here's the theory:
http://web.archive.org/web/20040223044157/wotmania.com/theorypostdbtheory.asp?ID=181&Category=RandLadiesAnd the Wotmania Theory Post had a lot of good ones:
http://web.archive.org/web/20080612102920/www.wotmania.com/theorypost.asp