Well, getting another cat was going to be my first suggestion, and building an outdoor enclosure was going to be my second. His behavior sounds typical for a Savannah, which is why breeders are sometimes reluctant to sell to people who live in apartments. Most times there are no issues, but some seem to adjust better to the confined space than others.
You can try the kitty DVDs and see if that will keep him entertained for awhile: http://www.amazon.com/GoCat-Cat-Sitter-DVD/dp/B000F6UOXC
There are also turbo tracks: http://www.amazon.com/Bergan-Turbo-Track-Cat-Toy/dp/B001RTTL1W/ref=cm_lmf_tit_2
Cat tunnels: http://www.amazon.com/ABO-Gear-Fun-Tunnel-Cats/dp/B000FOOO6C/ref=cm_lmf_tit_15
Laser chase toys: http://www.hammacher.com/Product/Default.aspx?sku=84165&refsku=83376
and of course the ultimate remote access cat babysitter: http://www.techhive.com/article/203...pointer-over-the-web-while-youre-at-work.html
I assume you have a variety of cat trees and scratching pads for him already. Is it possible to put up a small enclosure-type space on a patio or balcony so that he can go outside some of the time? The more variety of enrichment he has, the less mischief he is likely to get into, as you've obviously figured out by now...
You can try the kitty DVDs and see if that will keep him entertained for awhile: http://www.amazon.com/GoCat-Cat-Sitter-DVD/dp/B000F6UOXC
There are also turbo tracks: http://www.amazon.com/Bergan-Turbo-Track-Cat-Toy/dp/B001RTTL1W/ref=cm_lmf_tit_2
Cat tunnels: http://www.amazon.com/ABO-Gear-Fun-Tunnel-Cats/dp/B000FOOO6C/ref=cm_lmf_tit_15
Laser chase toys: http://www.hammacher.com/Product/Default.aspx?sku=84165&refsku=83376
and of course the ultimate remote access cat babysitter: http://www.techhive.com/article/203...pointer-over-the-web-while-youre-at-work.html
I assume you have a variety of cat trees and scratching pads for him already. Is it possible to put up a small enclosure-type space on a patio or balcony so that he can go outside some of the time? The more variety of enrichment he has, the less mischief he is likely to get into, as you've obviously figured out by now...