To fly a 45 pound system, especially something as big and expensive as an Arri 35mm camera (I'm assuming something in the BL series, or maybe an Arri III or II) requires a serious Steadicam, something which will cost a serious amount of money. Most Steadicams that are used by professionals to fly cameras like these are over $50,000 USD. While there are some homebuilt systems that can fly this kind of weight, and some lower-priced commercial systems (like the Glidecam Gold), probably even those will be out of your price range. Also, something to consider is that for any of these rigs, you will need to have a rig with 24v power (most 35mm camera setups need it) and good enough wiring through the post to power the camera (you really shouldn't be flying a 35mm camera with onboard batteries, and a power cord going to the rig is a big no-no). Also, most Steadicam operators will only work using Steadi-Mags, which are film magazines that displace the film vertically, instead of to one side or towards the front and back. The movement of film from one part of the magazine to another during the take is enough to upset the rig's balance!
Now, this certainly shouldn't defer you from trying to come up with a way to make your pictures steadier. For the 5DMK2, a stabilization system is certainly a quite attainable goal! And, for other cameras without all the restrictions that a big, heavy, complex, and expensive 35mm camera brings, stabilization can be a fun, exciting, truly captivating passion.
I hope some of this helps.
