eSATAp may become standard in the future, but most of the current eSATA ports in motherboards and laptops don't provide power through the ports. The solution is something like this: Newegg.com - ICY DOCK MB668US-1SB Aluminum body w/ partial plastic 2.5" Black USB2.0 & eSATA External Enclosure with One-Touch Backup (OTB) Function
The enclosure takes 5V power from USB, so this enclosure allows eSATA external HDs (2.5 inch form factor) for laptops.
I'm replacing SSDs in desktops with bigger ones, and I'll try one of those small SSDs in this cheap enclosure. My laptop has optical bay (SATA) and eSATA ports, so all three drives (OS, Audio, Samples) can be configured through SATA speed, like the way I do for desktops.