Is there an ERDAS ECW Plugin for ArcPAD 7.x?
The short answer is no. We are no longer providing ECW Plug-in for ArcPad 7.x . The ERDAS ECW Plugin for ArcPad used to be provided for free, but it was not maintained or supported.
FYI, In the next version of the ECW/JP2 SDK (v5.1) we are planning to support WinCE again, but this product is meant for ArcPAD developers, not users.