We plan to run our test environment inside ESXi 4 hosts on a couple of Core i7 920's with X58 mb's.
The hardware is very non-HCL which also means we forfeit VMware support. No biggie for a test environment already running two whitebox ESXi 3.5 hosts for almost a year without problems.
We don't need the onboard NIC's or VMFS on SATA, although it would be a bonus. We just need to get ESXi 4 installed and load drivers for some dual-port Intel PT adapters. The PT's are on the HCL.
If anyone has this working on Core i7 (or not), I would be very interested.