Check out this Channel 9 video on the WPD platform. It's full of demos - check out the one with a WPD driver for a blood glucose meter (22:00 timestamp). There are demos of the WpdInfo and WpdMon tools. WpdInfo and WpdMon are available in the WDK, while WpdMon is also available with the MTP porting kit. These are great to understand WPD and MTP! I'll post more information (along with links) on these later.