You might do well looking at Australian series racing HPVs. Very custom, but suspension is rare or nonexistant. The interior space created by rollcage requirements makes the basic styles more suited to commuting modification than Eco-marathon shells and chassis
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Phantom team forum seems to be the most active for the past few years, or search for "Pedal-Prix" for general images.
As for tires, the Michelin ecomarathon special radials, I'm not sure if they're available to the general public. Schwalbe currently has Tryker radial tires in commuter and lightweight racing versions available on request, 40-406 (20"x1.5"). The other popular option is Greenspeed Scorcher (40-349) and Duro slick (40-406) which were developed to replace Tioga Comp-pools which changed in design.
Looking closely at the wheels I would expect that they are cut from reinforced carbon panels - Pre-preg layers over a honeycomb core of aluminum or kevlar (Nomex) - with an alloy rim bonded on. An example (from a heavier material) is part way down
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