You don't need separate NICs for each IP, although that is a possibility. Linux is happy to assign up to 255 addresses per NIC, and that is how I would do it. For 2 SSL sites, assign 2 addresses in the 192.168 range you use on your LAN to this machine. Say for example you give the machine both 192.168.1.50 and 192.168.1.51. Make sure you assign just one gateway to the two virtual interfaces, something like this:
Code:
auto eth0
iface eth0 inet static
address 192.168.1.50
netmask 255.255.255.0
network 192.168.1.0
broadcast 192.168.1.255
gateway 192.168.1.1
auto eth0:1
iface eth0:1 inet static
address 192.168.1.51
netmask 255.255.255.0
That is from a Debian /etc/networking/interfaces file, but I believe that syntax will work on all distros, it is just a question of where that file is. In any case, that gives the box both 192.168.1.50 and 192.168.1.51 on one NIC.
Then on your firewall or router, use port forwarding or one to one NAT to map 75.A.B.C to 192.168.1.50 and 75.A.B.D to 192.168.1.51. Then you change your apache to do the virtual hosts by addresses rather than names. The post above by p_s_shaw has that mapped out clearly, and you'd simply have to add the location of the second ssl config for that site. You'd use internal addresses on the apache host, and map the external addresses to those local through your gateway/firewall/router.
Peace,
JimBass