Maybe he can make the 2 sections seperatly and each at their respective heights, and then bolt them together in the L-shape...or just place them together, no bolts.
I am hoping to get my DH to do the same thing...I am planning to have him use some reasonably priced cabinets under my cutting table so that I can have some covered (read hidden) storage!
Good luck with your project...and remember to share pics with us!