> I *really* need to build a custom kernel first (absolutely) because
> I have to hack the ne(4) driver, even in 1.6, in order to get on
> the network.

Have you tried just building the kernel?  Something like:

	unpack 1.6.2 kernel sources tarball
	unpack whichever 1.6.2 tarball has config sources
	compile 1.6.2 config
	edit kernel sources as desired
	run the 1.6.2 config on your configuration file
	make depend
	make

This worked for me building a custom 2.0 kernel while running 1.6.2.
Perhaps it will work the other direction for you?
Actually, going backwards you probably don't have to compile config,
just grab the 1.6.2 binary.