I came up with an alternative that should work well and doesn’t violate the warranty plus looks more professional than having USB dongles sticking out.
The PBXact 60 has two PCI-e expansion slots meant for telephony cards (to be installed by the end user). The customer doesn’t need those so I found a PCI-e adapter and SSD that screws right onto the card itself. It’s a tidy upgrade and my rough testing shows it to be around USB 3.0 speed. The OS picks it up as a second SATA drive. Components in case anyone else is interested in doing this:
