I've created kernel-isa and kernel-isasmp packages (currently i586, there'll be i686 version soon too). Basically, it is centosplus kernel with ISA Plug and Play, ISA and PCMCIA sound cards and ISA network cards enabled. The change to kernel spec file to add these two packages was fairly simple, and I hope this might find the way into centosplus kernel. If maintainer(s) of centosplus kernel are interested, I can email the patch for the spec file and four additional kernel config files.
I've tested it on my old laptop that has built-in ISA sound card (ESS ES1878). Kudzu and automatic sound card detection didn't work, however after I manually added entries to /etc/modprobe.conf, it all worked nicely. I had to manually specify io, irq, and dma settings in the options line, and I guess the same may be true for most ISA hardware.
I don't really have anything Plug and Play to test, and no ISA network cards anymore. Anyhow, if anybody does have, it would be nice if (s)he could test if all works OK. The Plug and Play is in kernel, no userland tools should be needed (hopefully).
The only sound card missing is Wavefront. The source code for device driver needs some updating (there seem to be a patch floating around somewhere though, haven't tested it yet). The way it is now, it produces unresolved symbols if compiled.
I see these packages mostly useful for folks with older laptops (ISA based sound cards, buying cheap PCI card is no option on laptops). Also for folks with older motherboards that have run out of PCI slots, but still have a few free ISA slots.
The packages are signed with my PGP key (same as the one used for this email, you can grab it from most PGP key servers). Key fingerprint is 46FE 7D24 2D50 566A FBF3 7395 4AE4 9AE0 D660 AA3F or something like that.