If you have any 3/4" thick wood at all, your in business!
Say you have a piece of 3/4" x 4" about 12" long, you can cut your blank (and many more) out of that.
Just use a heavier (#7 or #9) blade and draw a rectangle 3/4" x 5" in one corner and cut it out of that board on your scroll saw.
I know that you are going to say "But, I can't cut a straight line" however, that doesn't matter because you are going to cut your 3D pattern out of it anyway so who cares?
If your are looking for a certain wood to use, you can buy what ever you want and not worry about exact dimensions to start with. You could even cut it out of a 2" x 5" piece if necessary.
Just trying to help a bit.
