i'm happy as a ___________

A Clam ? I dunno.......I have heard that one , but I don't know what the clams have to be so happy about.
Happy as a pig in **** works , if you can get past the vulgar overtones.
Happy as George Zimmerman ? O.K. , we don't need to go there.
The harbor freight fire extinguisher works for show and tell , but if you have to put out an actual fire you will require some divine intervention to successfully do this.
Happy as Liberace before he had ever heard of that virus ?
I had no idea that fire suppression systems were so expensive to have refilled.
Did you go outside the automotive world and check with a commercial fire extinguisher supply house. We have a couple close to me and I bet they use similar stuff for computer rooms and etc. Might be worth a look.