Matthew Ng, a medical student in Singapore who coils at night, set out to fit a dual-resonant coil into a 50×50cm footprint that could still throw sparks as tall as itself and play MIDI files. The timing and feedback logic runs on an unmodified Steve Ward UD1.3b board. It is the real board, silkscreened "STEVE WARD 2008," wired here to its gate-drive transformer and a stack of 1:1000 feedback toroids. The half bridge is Ng's own double-sided PCB: two IGW75N65H5XKSA1 IGBTs off a 325 VDC rectified-mains bus, gate drive at 24 V through P/N MOSFET totem pairs with 33 V gate-source zeners clamping transients, and TVS protection across each switch. He drew it up as his own schematic and published the gerbers with it. A OneTesla SD-card interrupter feeds the drive optically so the coil can play music. Confirmed first-hand: first light at 30 VDC, and streamers to 350mm at the full 325 VDC with 50-100µs on-time.
Schematics and photos
half-bridge schematic 
half-bridge PCB layout
Sources
This is the card from the driver tree, written from what the builder published. Send corrections through the forum.