Denise,

I've never covered any of my books, but i know my local SB store sells material for covers. Such as a leopard skin and some furs.I would think you could cover it with any kind of material. A nice lavender satin would be pretty for a sister maybe pearls or beads glued on....... Just a idea
Viki

Here is one website that had a photo album covered with fabric that of course you could also use to cover a scrapbook.
Address: http://www.pioneerthinking.com/chphotoalbum.html

Below is a link to a website that had a fabric covered address book that I would think could easily be used for a scrapbook. Not sure these are what you wanted.
~Lynn~

Here is a link that might be useful: Instructions /Victorian Book Cover

Okay here is a cheaper suggestion:
Go buy a 3 ring binder with a plastic clear cover where you can insert paper into the spline, front and back. Then you can find SB paper ( you'll have to use 12 x 12 paper cut to size for the covers as 8.5 x 11 paper is too small) to match her favorite color, subject, etc... I have done this with SEVERAL cookbooks, and on the spline, I have used alphabet stickers to spell their name, (ie - David's cookbook)
on a matching piece of paper decorated with stickers, and then decorated the front and back cover just like a scrapbook page. It looks best if the same color paper is used as a background for all three sides. I have made several of these for cookbooks and albums and love them more each time I make one. Yours could perhaps say "Sisters are Forever Best Friends" on the front or back. The "D" ring style works best and if you have a large amount of pages get at least a 3 inch one. This will not work though if you scrap in a 12 x 12 size format. You will pay approx. $6.00 for the album which is a great saving compared to many overpriced albums, leaving you more dollars for scraping. Love Penny

thanks for all the help! Lots of ideas!

great idea look4angel. Very Clever