Pricing should be basically in line with the currently avalible Asus All-In-One systems that predate Windows 8 with similar specs:
Newegg prices are as follows:
ASUS ET2701INKI-B046C 27" All-in-One PC Intel Core i7 3770s(3.10GHz) 8GB DDR3 2TB HDD Capacity NVIDIA GeForce GT 640M 1GB Windows 7 Home Premium 64-Bit - $1,499.99
ASUS ET2701INKI-B030C 27" All-in-One PC Intel Core i5 3450(3.10GHz) 8GB DDR3 2TB HDD Capacity NVIDIA GeForce GT 640M 1GB Windows 7 Home Premium 64-Bit - $1,299.99
There really is no magic in terms of pricing here with this future Windows 8 All In One system or future Windows 8 Pro x86 tablets which should be comparable to many existing x86 tablets.
A 27” Apple iMac with Core i5 processor (2.7GHz to 3.1GHz), 4GB of RAM, 2560 x 1440 non-touch display would cost about ~$1699 to ~$1999. A Dell XPS One All In One 27” with non-touch 2560x1440 display starts at about ~$1300.