We know that VMware has a huge ecosystem of virtual appliances that run on their VMDK platform. Microsoft has the VHD platform and thanks to the publication of integration components for Linux under GPLv2, we can expect something similar for Hyper-V.
Virtualboy posted about the launch of the Appliance Test Drive. Microsoft has an existing library of trail products available. Partners have joined in with trial and/or free products based on VHD:
Citrix EVA for XenApp
The Citrix EVA for XenApp enables customers and partners to evaluate both online and offline application virtualization with XenApp 5 for Windows Server 2008.
DataCore Virtual SAN Appliance
Free, Ready to Run, DataCore Virtual SAN Appliance. This Virtual SAN Appliance software places shared storage for virtual machines and physical servers at your fingertips.
Athena for System Center Configuration Manager 2007
Athena-enabled device management functions extend and complement the native capabilities of Configuration Manager 2007 for Windows Mobile and Windows CE Embedded devices.
EventTracker VHD
The VHD is a pre-configured, fully functional trial of EventTracker. This image comes with EventTracker including change monitoring and the EventTracker Event Portal, Event Log Central.
ThinPrint .print Server Engine 7.6
ThinPrint .print Server Engine 7.6 is installed on Windows 2003 R2 and allows for evaluation of V-Layer, universal printer driver, bandwidth control and compression.
Check it out if you’re looking to evaluate some technology. If you’re an ISV then you should consider this as a way to provide pre-configured evaluations to customers. Part of the complexity for potential customers getting a trial working is figuring out those configurations. If you are an ISV then you can remove that pain from introducing your product to a new customer.