Customizing toys has been around for a long time.  This is typically called customizing and more recently kit bashing.  The idea is simple, take a standard car, chop it up, paint it, change the wheels, etc.  The sky is the limit when it comes to customizing.  Here you can find a listing of customized hot wheels cars.
Hot wheels, Custom Barracuda, redlines, vintage, Plymouth

Hot wheels, Custom Barracuda, redlines, vintage, Plymouth

4 $25.39 19m
HOT WHEELS RL 1968 CUSTOM CAMARO- RED BLK ROOF-TAB BASE

HOT WHEELS RL 1968 CUSTOM CAMARO- RED BLK ROOF-TAB BASE

$435.00 21m
VINTAGE 1967 CUSTOM COUGAR REDLINE HOT WHEELS ORANGE CH

VINTAGE 1967 CUSTOM COUGAR REDLINE HOT WHEELS ORANGE CH

5 $15.04 22m
Hot Wheels Since 68 Exclusive CUSTOM FORD MUSTANG *mint

Hot Wheels Since 68 Exclusive CUSTOM FORD MUSTANG *mint

1 $0.10 41m
HOTWHEELS custom '59 cadillac (1 64) MINT

HOTWHEELS custom '59 cadillac (1 64) MINT

- $0.10 45m
Hot Wheels 2008 Frist Editions 07of40 Custom 1977 Van

Hot Wheels 2008 Frist Editions 07of40 Custom 1977 Van

- $0.99 47m
1:64 CUSTOM '69 DODGE CORONET SEAN CASEY #22 RED SOX

1:64 CUSTOM '69 DODGE CORONET SEAN CASEY #22 RED SOX

- $3.99 48m
1:64 CUSTOM VW BAJA CHICAGO CUBS TEAM 90th GAMES WON

1:64 CUSTOM VW BAJA CHICAGO CUBS TEAM 90th GAMES WON

- $3.99 49m
1:64 CUSTOM '64 GALAXIE BILLY WILLIAMS #26 CHICAGO CUBS

1:64 CUSTOM '64 GALAXIE BILLY WILLIAMS #26 CHICAGO CUBS

- $3.99 49m
1:64 CUSTOM SET FORD BRONCO CAL RIPKEN JR. #8 ORIOLES

1:64 CUSTOM SET FORD BRONCO CAL RIPKEN JR. #8 ORIOLES

- $5.99 1h 5m
1:64 CUSTOM '64 LINCOLN EDGAR MARTINEZ #11 MARINERS

1:64 CUSTOM '64 LINCOLN EDGAR MARTINEZ #11 MARINERS

1 $3.99 1h 6m
1:64 CUSTOM HW SWOOP COUPE MIKE TIMLIN #50 RED SOX

1:64 CUSTOM HW SWOOP COUPE MIKE TIMLIN #50 RED SOX

- $3.99 1h 8m
1:64 CUSTOM '69 DODGE CORONET JIM PALMER #22 ORIOLES

1:64 CUSTOM '69 DODGE CORONET JIM PALMER #22 ORIOLES

- $3.99 1h 10m
Hot Wheels 40th Anniversary Edition "Custom Otto"

Hot Wheels 40th Anniversary Edition "Custom Otto"

$23.99 1h 17m
1:64 CUSTOM GRAND NATIONAL EDGAR MARTINEZ #11 MARINERS

1:64 CUSTOM GRAND NATIONAL EDGAR MARTINEZ #11 MARINERS

1 $3.99 1h 19m
Hot Wheels Nissan Custom "Z" Collector #600

Hot Wheels Nissan Custom "Z" Collector #600

- $1.99 1h 20m
HOT WHEELS WOODWARD AVE PICKUP & CADILLAC CUSTOM SET LE

HOT WHEELS WOODWARD AVE PICKUP & CADILLAC CUSTOM SET LE

- $6.99 1h 21m
HOT WHEELS 32 FORD PICKUP 57 RANCHERO CUSTOM TRUCKS MIB

HOT WHEELS 32 FORD PICKUP 57 RANCHERO CUSTOM TRUCKS MIB

- $6.99 1h 21m
1:18 SCHUMACHER ENZO HOTWHEELS CUSTOM W  DRIVER FIGURE

1:18 SCHUMACHER ENZO HOTWHEELS CUSTOM W DRIVER FIGURE

1 $19.99 1h 27m
1:64 CUSTOM '69 DODGE CORONET CAL RIPKEN JR. #8 ORIOLES

1:64 CUSTOM '69 DODGE CORONET CAL RIPKEN JR. #8 ORIOLES

1 $3.99 1h 27m