Lets take a quick look at www.danscomp.com and see all the parts we need to do this:

1. LSD compatible hub: DK DualDrive - $60.00
2. ACS SouthPaw (14 tooth!) - $17.00
3. BUILDING WHEEL YOURSELF: Free - but you may need new spokes ($8.00 minimum)

Can you just flip your cranks over? Yes, but the way cranks are designed with pedals, the pedals may come loose. This is a pain, but if you carry a wrench with you, use Loctite, and torque those pedals in place, then it may never be an issue. If you do end up getting new cranks:

4. New cranks: Profile LHD - $135.00

Minimum cash: $77.00 - Max: $220.00

Bash guard: About $20.00 and a good chain (KMC 410H) is $10.00 - so $30.00 to go that route.