What type of Certificate server?

Setup:
WLAN using PEAP-TLS.

Server1 - Win2k3E AD DC + DNS + DHCP + GC + IAS + Enterprise CA (issues
certs from domain machines usin autoenroll)
Server2 - Win2k3S AD DC + DNS + DHCP + GC + IAS

So we have redudancy in case of failure of server1 for DNS, GC, ADC, IAS
(radius). My big worry is if server1 fails we have no redudancy for cert
services.....so machines cant authenticate using PEAP-TLS and our entire
WLAN fails(!).

So - I want to add cert servicesw to server2....but I ma *very* confused as
to what 'sort' of certificate services I should be setting up. I know that
it shouldnt be another enterprise CA(!) but type of cert server should it be
to provide redudancy in case server1 is off air?

Any tips?

Al Blake, Canberra.
PS Please dont tell me I need more boxes - we cant afford any more.
PPS Any ideas with redudancy for DHCP - this is another service that I can
work out how you can have failover for (as you cant have two servers give
out the same address range - or can you?)