Yes, the grafting is posible. I recently found a sight that may be helpful. Since I am not sure how to do a link, I will just give you the Web address- www.bonsaikc.com/grafting1.htm

A Blue Spruce is not a fir???????????

Blue Spruce are known to backbud on old growth, but it is very haphazard. Don't count on it being even close to where you want it.

As far as shortening the long branches-you can as long as you preserve some of last years growth. It will bud and grow from the tips of the most recent years branchlets.

Vernon

P.S. Why fight with an extremely prickly species?

Vernon:
Thanks for the kind words and referral to my article. (You can add a link by typing the URL below the text box on a reply, if you want to put a link in a post you have initiated, that box will show up when you preview your message.) It, of course, only deals with Japanese black pine, but I believe the technique is the same for spruce. Grafting is a valuable tool for bonsai, and many great trees have been produced that way.

Erocki, first make sure your tree is in excellent health and very vigorous. When it is growing strongly, do your cutting back. You should always leave some foliage on the branches with conifers. Use the new buds that pop to improve your structure, then think about grafting if you don't get anything you can use.

Here is a link that might be useful: Sashi-eda Bonsai