Hi Robert,
I just checked it out and there is no easy way to make the thickness 1". All the geometry is set to .75" three levels down. That said, I modifid one of the cabinet bottom shapes for 1" and attachd the file. No guarantees but I bet you can figure out how I did this if you want to recreate. Just use the Edit Open command and check the geometry section of the first shape. Replace all the .75's with 1's.
Uhh, I guess I can't attach files. I just stuffed the vsd file up on the blog, go here to grab the file.
http://www.d-toolsblog.com/?attachment_id=2820
Good luck,
Adam