Hi,
I did develop/subclass vfp native controls to be XP look like controls. What I did is, subclass the base controls, and change the back colour, border colour, border style, special effect and etc to make it look like XP control.
However, that is some limitation here, the color of option, check box may not able to be changed as XP.

I also build my own robust classes to be my grid header, toolbar button base on the concept of XPFORM classes.

That is what I did, and my client look happy for it.

HTH