Neither my 15.5 USG SS keg nor my Brewhaus Premium Kettle are attracted by/to a magnet. Induction heating would not be possible for these. In addition to the weight, the curved shape of a keg within the base would also present a problem for flat induction surfaces. The cost of getting a curved arrangement (like my Induction rice cooker has) would be prohibitive. I think it would need to be custom built.
On the other hand, Winware produce these induction-compatible stockpots from 8 to 80 qts ($44-$197): http://www.amazon.com/gp/product/B001AS81CA
The smaller sizes might be good for a stove-top still used on an induction cook-surface. One possibility might be to have a large grid or support with an opening for an induction hotplate to be spring loaded against the base of the pot/boiler. Many/most/all(?) induction burners have "size recognition" issues - they will not work with pots outside their sensing range. As much as the idea appeals, it might be cheaper to buy premium booze for the rest of my life than to seriously explore induction heating with keg-sized boilers (and I wouldn't consider that option!)
Needing indoor stilling (Canadian winters mean gas/propane is not an option!!!) I've taken this route:
My 1500w cast iron hotplate works well with the flat base of the BH kettle for "dirty"washes, . It takes 90+ minutes to get the first drops of distillate.
I'm using internal elements for all cleaner/clear washes washes. Two of these 1650w/120v extra-low watt density elements work well in my BH 8usg kettle. (each element actually draws 117v/1500w (120 to 122v measured at the receptacles with no-load ): http://www.amazon.com/RELIANCE-WATER-HE ... 324&sr=8-1
I get my first drops of distillate at about 35 minutes, Power control is by means of 2 router speed controls: http://www.amazon.com/MLCS-9400-Standar ... 077&sr=8-1
I have these extra-low watt density elements waiting to be fitted to my keg: http://www.amazon.com/Reliance-9000396- ... 880&sr=8-2
Preheat with lower element only at 5500w/240v for first drips in 30 to 40 minutes (or use both at 240v for a 15 - 20 minute warmup if power is available) then switch to both at 1375w/120v - each using the router controllers.
I have fairly good, inexpensive heat control. For better control the long-term plan is, eventually, to replace the router controllers with one MK-5500.
To return to topic:
While I favour tech/gadgets, for our purposes I'm not convinced that induction offers any significant advantages/savings/efficiencies over internal electric elements, where close to 100% of electrical energy is converted to useful/useable heat. Further I would suggest that heat control, especially with the MK-550 (or MK-1100) might well be significantly superior.
BUT..... I'm open to persuasion