Australian High Performance Catamarans, that same place I bought my very nicely made tornado rudders & castings last year, just emailed me about tornado boat covers. They make 'em in two flavours... a lightweight polytrap and a heavy acrylic coated canvas...$300 & $700 AUD respectively. This is so much cheaper than the acrylic canvas one made by Kinder Industries in RI ($980 USD), esp. after factoring in exchange rate. Shipping is a mere $80 AUD. Heck, this is even cheaper than a fellow Aussie competitor..RedHead Sails...they make 'em for $1300 AUD, $250 AUD shipping to CA.
Mike.
Make sure they use DHL for shipping. I have bought sails from GMSails of AUS and they have always come to my door with no hassles using DHL. I can't say that about two other companies. You will receive a call from US Customs and then a bill [Import Duty] that must be paid in the USA based on the sales price.
Its truly a "World Economy".
thom
Think they could cut one for an Inter 20? It's a bit more narrow (8'6" vs. 10' wide), and the bows are square... The TOP GUN folk (that make Tornado covers in RI) don't have one for I-20, or at least that's what they claim....
When I had the rudders sent, I think it was dhl...they required a signature upon delivery, so I had them sent right to my work shipping address. Picked 'em from our shipping guys later that day.
No duty/taxes were imposed. 
Mike.
Give them a shout ( AHPC )
to find out. They do take a little while getting back via email...and watch out for the time change when calling directly.
I thought "Top Gun" was the name of a material used to make boat covers, not a company name in RI. The only place I 've heard of in the states making covers for tornado is Kinder Industries. Can you provided a contact for this Top Gun place?
Jay,
I thought Murray's Marine bought them out but, I was mistaken. Check out the link below. They have TopGun covers for $542.
Dave Salty Dog, Top Gun Covers
I've got a set of Top Gun trailerable hull covers for my 6.0 and I love 'em.
I'll give 'em a look-see...
No listing for Tornado on the products page...perhaps they can make one up special order.
Mike.