Saab is revealing a compact, ethanol-powered crossover expected to be named 9-1X.
Toyota will show off its iQ concept which seats three adults and one child and is less than three metres long.
Small soft-tops are also in vogue, with Audi showing an A3 convertible that will compete with the BMW 1-series convertible unveiled in Detroit in January.
"There's a downsizing effect," says Mr Willis, who is appealing to the youth of Europe with its small, sporty Soul. "We're seeing a change in the mix of vehicles."
The market for downscaled sports utility vehicles (SUVs) is another growth area, targeted by amongst others by Toyota, which is launching its Yaris-based Urban Cruiser.
Infiniti will show its luxury FX SUV
Though this is not to say competition is easing in the market for mid-sized SUVs, or crossovers, which Volvo is driving into with a slimmed-down version of its larger success story, the XC90.
Volvo's new vehicle, dubbed the XC60, is based on the Land Rover Freelander platform and will go head-to-head with Audi's Q5, BMW's X3, and Mercedes GLK.
Renault is also entering the segment with its first SUV, the Koleos, based on alliance partner Nissan's X-trail.
The new model brings the number of rival models in this market segment to 25, according to Renault, which points out that some 5% of all vehicles sold in Europe are in the SUV/compact crossover category.
Diesel electric hybrid SUV concepts are also on display, with BMW making much ado with a version of its X5 and Mercedes displaying a GLK.
Both hint at how most automotive companies are countering criticism from environmentalists with efforts to reduce emissions by introducing new engine technologies.
In the top-end of the market, Rolls-Royce is expanding further with its Geneva-launch of the new Phantom Coupe, which is kitted out with a 6.75 litre V12 engine.
The car will be a rival to Bentley's Brooklands Coupe.
The Rolls-Royce Drophead Coupe will be on show in Geneva
Less brash and considerably cheaper are luxury models from Infiniti, which is arriving in Western Europe in the autumn, two years after the Nissan subsidiary was launched into the Russian market, and a full two decades after its US launch.
The marque's arrival is accompanies by the world premiere for its FX model at a private event on Tuesday night.
The new Infiniti FX is gunning for customers currently eyeing full-size SUVs from BMW and Porsche, while its two other European models will compete in the same segments as the 5-series and 3-series BMW, or the E-class and C-class Mercedes.