Damn - I just lost my post due to a time out

Sounds like a Swiss Army Mower

Here goes again:

1. I tried this method and it's not as easy as it sounds to get working 'well'. Once setup properly however, it's the simplest solution by far!
2. I'd like to do this eventually - if the alternator was beefy enough, you could reduce the size of the required batteries considerably as the alternator could play a big part in driving those too.
3&4. When you've got it...why not?

Re the weedwhacker - good idea - the one thing I'm left to do after a session of hard mowing is to manually trim the edges... oh the humanity . Incidentally, have you seen the 'Lawnadillo'?
[link=http://www.honkernet.net/ahs/departmental/Robotics_engineering/Lawnadillo.htm]Lawnadillo[/link]
[link=http://www.popsci.com/popsci/how20/aa4f2c9363e0d010vgnvcm1000004eecbccdrcrd.html]How-to on Popular Science Mag[/link]