Can any Austin-Healey Sprite MK II or later be modified to accommodate three people? I'm absolutely in love with these cars, but the exclusively two-seater accommodation is very restrictive.

The question is academic - it wouldn't pass it's MOT even if you could fix one - and seat belts don't work well on the roof!
Regards.

And can i get one in the U.S.? if so where? i have fallen in love with this car. it is too adorable.

Love the healy's... Ive seen sprites as low as the 1000 dollar range but if you want even a decent all around running and driving example I would say from $3K (still pretty low on the scale) and up depending on condition...

Also forgot to mention you can find them in the U.S. ebay is a great spot to find a wide variety...

If you have the cash and want a pristine one.. I would check with classic auction houses and etc...

Can cruse control be installed on a 1967 Austin Healey Sprite.? Can cruse control be installed on a 1967 Austin Healey Sprite.?

Companies such as J.C. Whitney, Autozone sell several aftermarket cruise control kits, many of which are actually made by a single company called Rostra.If you have any doubt that your vehicle can generate sufficient vacuum volume, consider an electric kit not a vacuum kit.

The kit consists of a servo box containing an electric motor-operated throttle actuator and a microprocessor board, a vehicle speed sensor for the brand of vehicle you specify at the time of order, a turn signal or dash panel mounted control head and a bag full of misc hardware. Installation consists of attaching the actuating cable to the throttle linkage, mounting the servo box somewhere convenient, setting some switches in the servo for the application at hand, installing the speed sensor on the speedometer drive (if needed) mounting the control head and providing power to the unit.

Since your vehicle does not have an electronic speedometer or electronic transmission, you’ll need to mount magnets on the drive shaft for the VSS (vehicle speed sensor)

If you are an experienced mechanic and familiar with your vehicle, you can perform all the work in about an hour (except the magnets on the driveshaft, which requires some effort to get correct).

Anyone know if there is any type of gasket or trick to keep water from entering between the outer front fender and the subframe? There is a gap betewwn the two, along the radius of the inner well, begging for water-gathering.
Also, are there drainholes anywhere? I know they get clogged over time. I am repainting mine, and want to make certain water does not become trapped anywhere.

The front fenders on "Spridgets" have a drain hole on the lower portion of the front fender. If that is insufficient, experts with the Chicagoland MG Club recommend that owners make their own drain holes to reduce the possibility of corrosion.