There is a free version of VB to create activex controls,
in a control you can add all standard controls. It's called vb5cce. Visual Basic 5 Control Creation Edition.
If I remember correctly you can create various size controls with it, and aswell save the control. I think the tool needs only a small tweak to understand the ctl files produced with it...
Ohh and in a control you should be able to run any vb5 code aswell.
Or you create the forms in VBA and say export
It shouldn't be hard to write a perl / bash / something script to read frm's or ctl's