It's feasable but as noted above by Peter, you'll need to go through and change a lot of the code that assumes certain things about the architecture it's running under.

Just having 2.2.x isn't enough. 2.4.x has most of these changes already done for you but 2.4.x doesn't work on the car player unfortunately. I guess you could back port the 2.4.x ReiserFS code but that is also a lot of work.

We can get most of the gains of using ReiserFS like the journaling by using the Ext3 code and the increased performance when dealing with large directories can be fudged by using Mark Lord's fidshift app along with v3.0a