This guy has Pro for $45...which can be extracted from the disc.
https://forums.macrumors.com/threads/306585/
I believe the terms of the license that comes with the VPC/Windows combo mention that the XP installation is to be used with VPC only. Not saying it can't be extracted, but it's allowed under the EULA.
Installation and Use. You may install, use, access, display, and run one (1) copy of the
Product on a single computer, such as a workstation, terminal, or other device
(“Workstation Computer”) on which you have also installed (and which is compatible
with and capable of directly executing) any version of the software product distributed
by Microsoft Corporation and known as Virtual PC for Mac (“VPC Mac”), solely for use
as a “guest” operating system running in conjunction with VPC Mac.
what is the difference between OEM and Retail?