Slinkey, the Lambo wasn't a Muira, was it..? Not sure if there were any other sideways mounted V-engined Lambos... Same as you see at the beginning of The Italian Job (original). Another thing it had in common with the Mini was that its gearbox ran in the engine oil, in the sump of its V8.
The Rotary Valve is most likely listed somewhere on here:
http://www.dself.dsl.pipex.com/MUSEUM/P ... alveIC.htm
The cool thing about a rotary valve is that it doesn't have to be the same shape as a standard poppet valve. You could have a "two valve" engine, but those two valves could take up the vast majority of the area of the top of the chamber, and the rotation of the tube minimizes the flame's time on the valve, keeping it cooler... Hopefully those Coates engines guys have found ways around the sealing, wear and dirt issues...
I only brought up F1 because the majority of the advantages on a Mini with solenoids would be down to getting rid of pushrods. But Minis have been over 10,000rpm... Otherwise, you need to look at it to replace the carbie/throttle body.
On the F1 point, Renault actually did use Solenoid Valve Actuation in F1. They used it when they came back into the sport around 2000, in the Bennetton chassis. That's why they had their wide angle V10's. Ilmor didn't like it, because they didn't believe it was worth the effort - too much extra weight at the top of the engine, higher C of G. Thus Renault's wide engine. But I'm not sure they still use it - they certainly now use a narrower bank angle. Have a look at these couple of links:
http://www.grandprix.com/ft/ftpw012.html and
http://www.halfbakery.com/idea/Cam-less_20Engine
Something interesting in the second link - they do point out that a solenoid in this application would basically need to be like a speaker. And speakers can run at over 20,000Hz (even higher, just that no human can hear it). That said, you could "musically" tune an engine - the on/off pattern required for controlling the valves would look similar to a "clipped" soundwave through an amplifier... Although it would be one wave, then three wavelengths of silence, then one wave... Valve opening would be volume (amplitude), and frequency is pitch... Is that complicating it?!
There only reason we have valve springs is to hold the valves shut, as in to stop them bouncing off the valve seats. There is an alternative - desmodronic valve actuation, ala Ducati. They don't need springs, a second cam holds the valves shut. If you have a dual acting solenoid, it would close the valve and hold it shut - theoretically you shouldn't need as heavy a spring. The spring would only be used as a safety measure. The main time when you need the valves shut is under compression and power, when all the forces are pushing the valves shut anyway. When it doesn't shut in a cam engine, it's often a combination of bouncing and resonant points in the spring, which combine to stop the valve seating. That's why they do multiple springs on valves - not (just) to get higher closing pressure, to reduce resonant frequencies in the springs. So the solenoid's strength might not need be as high as you might think... It's just speed and reliability.
It's all fun to think about... Even if it's just theory at the moment, and, for me, likely to stay that way!
If rotaries were the answer all cars would have em... the fact only one company made them work and it sent another to the wall trying tells you something. 
Dam i`m smart hey??? 
The car for which they invented the word "supercar". The first Lamborghini, from memory. Before that (and excluding a few show cars), Lamborghinis were tractors. And some still are. Literally. If it's geniune it would be worth an absolute mint... They were very rare...
You got me, Morris 1100... I couldn't remember for sure whether it was an 8 or a 12, I thought a 12, but I had 8 on the brain... So I tried to keep myself from putting in either number... But I missed one spot... 
