Hi Richard,
From a VFP perspective, Savanah Brentnall's Object Oriented Programming in Visual FoxPro - although a 3.0 book, is excellent. Also, if the Hentzenwerke books are out yet, what I saw of Markus Egger's was really good too and from there you could progress through the rest of the series. Rebecca Wrof's (spelling) "Designing Object-Oriented Software" also sounds like a good fit for where you're at right now. Then there's Design Patterns, a System of Patterns...