Is there an easy way to update your own kernel?

[Frank Leonhardt]

I suspect there's no answer to this, but I'll ask it anyway.

I have some tweaked drivers on my server cluster. I'd like to update 
FreeBSD, but obviously keep my driver tweaks. I've found two ways of 
doing this:

1) Upgrade from source, copying my own driver source over the "standard" 
versions.

2) To save building everything on every machine, do a source upgrade and 
then copy my custom kernel into /boot (using sftp) after a binary upgrade.

I *could* split the drivers in question out of the kernel and load them 
dynamically, but, AFAIK, there's no way to replace an in-built kernel 
driver by loading an external module - you have to recompile the kernel 
without it or it's ignored. I'm certain this used to be the case anyway.

Has anyone got a better way than either of the above?

Thanks, Frank.