Why did my 2004 Dodge Dakota Engine Go on Fire Moments After Starting?

Why did my 2004 Dodge Dakota engine immediately start spewing white
stinky smoke
and catch on fire immediately after starting?  

Facts:  
- 2004 Dodge Dakota Quad Cab 4x4 Manual Transmission (stick)
- Have owned 5+ years as 2nd owners
- This is an extra vehicle and is rarely used
- Has a manual transmission/stick shift
- No aftermarket stuff from what I see but for a radio
- Was mild and dry early fall in NY weather
- Regular service & inspections
- Came with 120K + miles, we've added under 2K total in 5+ yrs

Immediately after start I noted white wispy smoke from under hood that
smelled bad.  I
drove it quickly down the driveway about 40-60' to the street to get it away
from my
house and car in case it became a fireball, and shut it off.  

It took me several minutes to get the hood open and it seemed to have died
out.  It
seemed to me smoke was coming passenger side, more towards the back of
the
engine, nearer the windshield.  Didn't seem to be alternator area but I don't
know.

I considered restarting it to back it up and away to a better spot but changed
my mind
after a quick turn of the key - it still has a connection and the starter seems to
turn over
but it was weird - so not going there.   

The past owner I would call mechanically abled (owns tire store)did an
aftermarket
radio installation when he owned it, but the rest is basic factory. I never ever
turn on or
use the radio because it has incredibly annoying flashing color changing
lights and
noise.   

What could cause this fire?  I understand Dodge has used parts from the
1500 trucks
on some Dakotas, and 1500's do have lots of fire reports though I don't yet
see
Dakotas.  I plan on having a Dodge dealer tow it to investigate and fix it.  Any
ideas
where they should look?  Thank you so much!