I do use sfe driver from Masayuki Murayama to get networking and I use patched version of ata driver to get DMA working with internal disk on my laptop. Now I do install new SX versions on my laptop over the network as it's much faster and I do not have to burn new set of CDs every time new SX is out. With New Boot Architecture all I do is:
1. copy x86.miniroot file from /tftpboot
2. un-gzip file
3. using lofiadm mount x86.miniroot as UFS
4. install sfe driver with base_root changed to mounted miniroot
5. copy patched version of ata
6. umount file and gzip it again
7. put the gzipped file on /tftpboot with different name (x86.miniroot_laptop)
8. change menu.lst in /tftpboot/boot/grub to use new file
That way you can customize x86.miniroot in any way you want. As with New Boot Architecture no more Real Mode drivers are needed you can put there standard drivers for RAID, SCSI, etc. adapters and it should work.
btw: although it's good to copy driver packages to miniroot or install server too, so after the installation, before system reboots (I choose to manually reboot after install) you can install this drivers to newly installed system. In my case just before a reboot I copy ata driver and install sfe driver. You will find newly installed system under /a mountpoint.