https://cseweb.ucsd.edu/~hovav/dist/cloudsec.pdf (2009)
Edit: we describe an empirical mea-surement study focused on understanding VM placement in the EC2 system and achieving co-resident placement for an adversary. To do this, we make use of network probing both to identify public services hosted on EC2 and to provide evidence of co-residence (that two instances share the same physical server). In particular, we utilize nmap, hping, and wget to perform network probes to determine liveness of EC2 instances
The hard disk contention channel was used in Section 6 for establishing co-residence of instances.
Are you speaking generally or specifically addressing a shortcoming of the linked paper which demonstrates a methodology to determine whether or not two AWS VMs are on the same physical host?
After a brief review I still don't see any mention of "hardware info" you mention as assumed being available.
Edit: If something has come up since 2009 with this specific paper, I'd appreciate the heads-up!
> A single account was never seen to have two instances simultaneously running on the same physical machine, so running n instances in parallel under a single account results in placement on n separate machines