Are you transforming the bounding boxes into world coordinates somewhere else? Otherwise, you need to add some code to transform the bounding boxes from model space to world space. I guess what I'm saying is, without your bounding box code I don't see an issue.

Here's a few resources I frequent:

Sgt. Conker - results from the 2010 tutorial contest they held, there's a lot of decent stuff in here.

XNA Developer Survival Kit 2 - Nelxon's list of XNA Resources categorized.

Mage Defender Deluxe - XNA game with source.

XNA Tutorials - From the same guy as Mage Defender Deluxe a set of XNA 4.0 shader tutorial.

Lua into Games - Wrote for WPF games, but can be adapted for XNA.

tIDE and xTile - tIDE (Tilemap Integrated Development Environment) and xTile, a tile rendering engine and a fully featured level editor.

XNA 4.0 Game Engine - A game engine implementing a Light Pre-Pass Renderer, there are several blog posts after this one where he slowly adds more features.

XNA Game Programing Adventures - SixOfEleven's website, lots of useful things there.

I've been looking at Dream.Build.Play for a while now, It'll be interesting to see someone creating an entry for it.