From what I understand, you could run SQL on the peer to peer. SBS 2003 does have VPN working with Remote Web Workplace, which is all you would need anyway.
If you purchased a server $2,000 basically, maybe a bit more, you would then purchase SBS 2003 Standard or Premium $500 then 5 CALs $350 if you had more than 5 PCs including the server. Otherwise, you don't really need anymore CALS except for antivirus, if you want server centric AV. SBS 2003 has pretty good NTBackup, although some 3rd party ones are better. BackupAssist $200.
It can get a bit pricey but the functionality and security are well worth it.
But, I still would check out LogMeIn
www.logmein.com Hard to beat. Very good and FREE.
