Both HM55 and HM57 Express
are designed to run with LGA 1156 socketed Intel Core i7, Intel Core i5, and Intel Core i3 processors - and come with <= 14 USB 2.0 and <= 6 SATA-II only. Same interface specs (but smaller numbers) on the Atom counterpart NM10 Express.
What you see on these mATX boards e.g. made by Asus, Giga, or MSI (again not for Atom...) are SATA-III by e.g. by additional Marvell 88SE6111 and USB 3.0 by NEC controllers. No doubt, HM55/HM57 are potential candidates for future bigger TS, e.g. for replacing the TS-809 with SATA and SAS disks - but certainly not for a 20W platform.
All are in the US$ 200 range without a CPU - too much for replacing the actual Intel Atom Dx10 / ICH9 combinations. So please let's stick and compare apples to apples (lowercase intentional).
There are eSATA ports on the existing products, so there is no hurry.