Yes there is. rename your original uname to something like uname-wrapped and create a script in the same location called uname, that runs this uname-wrapped binary with the parameters and output alterations you need. For example, if you want to change the kernel version inside the output of uname from "2.6.7" to "2.6.9" put the following into your uname script:
uname-wrapped $@ | sed 's/2.6.7/2.6.9/'
this is called "uname hack"... you may google for it.