AFAIK it is not possible to fit a quad port Ethernet card into alow-profile PCI slot. The 4 RJ45 ports need more space than allowed by thePCI spec.
Actually the card in the tinyurl link I sent claims to fit the half-height slot of the HPQ DL320 G3 (I have a 3Ware SATA RAID card in the other).
I don't know how they do it. In reality I'd only need three but it seems that it is either 2 or 4...
Arrigo