odd behavior of node_modules/require with tilemill and node v0.6.x on mac osx

require_error_tilemill_node_v6.sh

$ node -v # compiled from latest branch
v0.6.7-pre

$ npm -v # installed like npm cache clean; npm install -g npm@alpha;
1.1.0-beta-7

# ensure step is available
$ node -e "console.log(require.resolve('step'))"
/Users/dane/projects/tilemill-node-v6/node_modules/step/lib/step.js

# NODE_PATH is not manually set
$ echo $NODE_PATH


# run tilemill
$ ./index.js 

node.js:201
        throw e; // process.nextTick error, or 'error' event on first tick
              ^
Error: Cannot find module 'step'
    at Function._resolveFilename (module.js:334:11)
    at Function._load (module.js:279:25)
    at Module.require (module.js:357:17)
    at require (module.js:368:17)
    at Object.<anonymous> (/Users/dane/projects/tilemill-node-v6/models/Exports.server.bones:1:245)
    at Module._compile (module.js:432:26)
    at Object..bones (/Users/dane/projects/tilemill-node-v6/node_modules/bones/server/plugin.js:32:12)
    at Module.load (module.js:351:31)
    at Function._load (module.js:310:12)
    at Module.require (module.js:357:17)

$ cd /Users/dane/projects/tilemill-node-v6/models/
$ node -e "console.log(require.resolve('step'))"
/Users/dane/projects/tilemill-node-v6/node_modules/step/lib/step.js

$ cd ../node_modules/bones/server/
$ node -e "console.log(require.resolve('step'))"
/Users/dane/projects/tilemill-node-v6/node_modules/step/lib/step.js

$ cd ../../
$ cd ../
$ export NODE_PATH=`pwd`/node_modules
$ ls $NODE_PATH
JSV               express           millstone         optimist          semver            tilelive-mapnik
backbone-dirty    jsdom             mkdirp            passport          sphericalmercator underscore
bones             jshint            modestmaps        passport-oauth    sqlite3           wax
carto             mapnik            node-markdown     request           step
chrono            mbtiles           npm               sax               tilelive

$ ./index.js 

node.js:201
        throw e; // process.nextTick error, or 'error' event on first tick
              ^
Error: Cannot find module 'graceful-fs'
    at Function._resolveFilename (module.js:334:11)
    at Function._load (module.js:279:25)
    at Module.require (module.js:357:17)
    at require (module.js:368:17)
    at Object.<anonymous> (/Users/dane/projects/tilemill-node-v6/node_modules/npm/lib/utils/ini.js:32:10)
    at Module._compile (module.js:432:26)
    at Object..js (module.js:450:10)
    at Module.load (module.js:351:31)
    at Function._load (module.js:310:12)
    at Module.require (module.js:357:17)

$ ./node_modules/npm/bin/npm-cli.js -v
1.1.0-beta-7

$ ls /Users/dane/projects/tilemill-node-v6/node_modules/npm/node_modules/
abbrev      ini         node-uuid   proto-list  rimraf      slide
graceful-fs minimatch   nopt        request     semver      which