Well, I was finally able to get around and make more progress with the Harvest engine. It's still in the ridiculously early stages, but it feels good to actually make some more progress. I wired up (again (and got it working properly this time)) a C++ Makefile project in order to build the solution (the engine + the sample application) using the NAnt build project from within Visual Studio. Last time I tried it I couldn't get intellisense to work on an ongoing basis. It turns out that it was an easy fix. I'm not exactly comfortable with it, but at this time building a solution builds both with devenv.exe (aka Visual Studio (this helps Intellisense continue to function properly)) into a temp directory, and then builds it again with the C++ makefile project (e.g. the nant build script).
Outside of the build and development environment, I was able to get the Vertex Manager and Vertex Cache working. The sample is ridiculous right now. It just shows two animated triangles and an animated square, but the manager and caches are working nonetheless :D. The next step is to wire up texturing. Once texturing is wired into the Vertex Cache, the bulk of the rendering engine is complete. All that would be left after that is to implement lighting. All in all, good progress.
Sooner rather than later, it looks like I'll finally be able to get around to implementing my own sprites and maps. Yee haw!