Hmm.. yeah. A lot of them say "support up to 750 GB" but I think that's just because when the spec material was written that's all there was. I don't know of any reason why they would support 750 but not 1 Tb.
for example :
http://www.satagear.com/SATA-PRO-35A..._Firewire.html
NEW Ultra Fast Oxford 924 Chip with Firewire 800 / USB 2.0 ports and eSATA port Works with drives up to 750GB SATA I and SATA II Spec. 3.5" SATA HDD to eSATA/USB2.0/FireWire800 Enclosure