If you haven't yet, I'd recommend reading the "Blue Book" (Smalltalk-80: The Language and its Implementation) by Goldberg. It has a very holistic approach and, as such, is one of the most accessible and pleasant books describing a computing/programing environment one can find.
I also recommend reading http://www.mirandabanda.org/bluebook/bluebook_imp_toc.html once you're done with the blue book; the VM is a two weekend project in any compiled high-level language (I used Rust) and it's not hard to make it performant enough for real use. I think my timeline was ~2 days for the initial implementation, 2 days for fixing up small bugs (mostly in primitives), and then 2-3 hours of minor tweaks to get the VM performant enough to be comfortable.
BTW, somebody typed the VM source in from the blue book and posted it online. You may find the resources on that page useful: http://www.wolczko.com/st80/
