Another rocket water thread

I know it's my first post, bear with me.  I've been learning about rocket stoves for about 3 years, and I finally found this forum along with donkey's forum.  I'm looking for the fastest way to heat any amount of water from 55 gallons to 350 gallons.  Thoughts are coils of tubing in or outside the heat riser with a pump to push the water around, or a large tank simply set on top of the output with the exhaust vectored around it like an institutional rocket stove...?

If i can do this logically, mind you I'm not really looking to be too cheap about it, I hope to use it in a business within the next few years.  (If the business doesn't work out, at least I'll have a few models setup and can heat lots of water and sell tickets...maybe my watched pot WILL boil).

Conditions : water starting temp 60-70 F
Water end temp 180-210 F
Tank possibilities: stainless if directly fired, or heavily insulated if indirectly fired...
Fuel:  Cord wood of varying types (hopefully mostly hardwood)
Hopeful Time:  <2 hours for 200 gallons  (faster per gallon the better)

I know you think i'm crazy, but in donkey's forum, there is a website where a guy claims to bring to boil 40 gallons in 30 minutes with a less refined display (keep in mind it's not 212F boiling...he's heating a wash of water/ethanol mix...boils around 176F...not too shabby though if he's correct!)
http://donkey32.proboards.com/index.cgi?board=cooking&action=display&thread=305

Any advice

TPS

I have had similar ideas. I would like to heat close to 1500 gal of water for a thermal mass in my 20x40 greenhouse.  I live in Michigan and would like to be able to sustain 65 degrees in the winter.  I was thinking of digging a trench, filling it with a pond liner, and submerging a 30ft long 8" exhaust pipe off a rocket mass heater in the water.  Any comments or ideas would be much appreciated.