eSATA is indispensable for home hyper-v Lab, based on a regular laptop (that you do not want to format or something) and a HDD connected via eSATA. You can install your hyper-v host on external HDD without any speed compromise.
On my Samsung R580 there is eSATA. I have also a regular SATA HDD 2T and HDD docking IcyBox
Works fast and I have 4 Windows 2008R2 servers running in my evaluation lab. I d not need to buy a separate PC for that.