Some of you have probably already seen these, alternators that look like generators. Bit expensive though but tempting, some other interesting stuff on this site as well
Cheers Mick
http://www.autoelectricsupplies.co.uk/product_list/141 (http://www.autoelectricsupplies.co.uk/product_list/141)
http://www.gener-nator.com/
Another company that does them