The MD1200 is just a disk enclosure. It doesn't care about the drive size. The question should be; does the PERC H800 support 3/4TB drives. The answer to this is that it does support (enterprise class) drives over 2TB (Dell sells the combo). Obviously; don't use desktop class drives in a setup like this.
Does anyone have experience with 3 or 4TB drives in a MD1200 w/ H800?  Looking at the documentation (ftp://ftp.dell.com/Manuals/all-products/esuprt_ser_stor_net/esuprt_powervault/powervault-md1200_Reference%20Guide_en-us.pdf) it looks like 2TB drives are the largest "supported".  Will the MD1200 recognize all 3/4TB of a 3/4TB drive? Thanks for any feedback!
MD1200 + H800 w/4TB Drives