For the most part, most current Intel server products support Windows Server 2008 and thus SBS 2008.
For an up to date list, check out: Server Products: Status of Server support for Microsoft* Windows Server* 2008.
Note that server board S3000AH shows "In Progress".
We do have our SBS 2008 Blueprint Springer Spaniel's SBS 2008 running on that platform with an Intel Xeon 3070 Dual Core CPU, 8GB Kingston ECC, SRCSASRB RAID controller, 320GB Seagate Enterprise SATA in a RAID 1+0 array, all mounted into an Intel SC5299DP server chassis.
That box has been in "production" since late August and has had no issues whatsoever with SBS 2008 RTM. We had some issues with SBS Cougar Beta, but they were primarily due to driver compatibility with the young OS and one of the Seagates developing some bad sectors.
As always, test things out and run at least a 72 hour burn-in on the server before allowing it out into production.
Microsoft Small Business Specialists
*All Mac on SBS posts are posted on our in-house iMac via the Safari Web browser.