FWIW, here's what I've done with my wagon:
Got both front and rear door seals here - $60.00 per pair, Metro brand.
http://www.dannoenterprises.com/wchevy.htm
Look good, installed easily, but OEM would be better. The driver door has an air leak that I just can seem to get rid of.
For the seal around the tailgate - the one that goes all the way around th frame, i used the Voyager seal, as recomended on this site.Works great, doesn't look like the original. Looks fine to me, I also used it to replace the seal around the spare tire area.
Cheap and plentiful at your local PAP.
For the top of the tailgate, I used the tailgate seal off a late 80's Blazer, also from the PAP. It seals fine, but there are two problems with it:
1 - It doesn't look like the original; it's smaller. No one else notices it.
2 - The Blazer isn't as wide as the Malibu wagon, so I had to get two of them and cut to fit. So there's a seam in the center. Doesn't bother me and I haven't found any leaks yet - but I'm in Phoenix, so not much rain, either.