Hi Harry,
OK, I'll give it a go.
There were 250 monks precepts and 348 precepts for nuns. Let's assume the latter include the former and since we're all for equality here at Treeleaf let's assume those 348 rules apply to males and females for our purposes. I think the Buddha taught for about 45 years. Also let's assume 2500 years have gone by since then (since there is no real concensus on his dates of birth/death).
So, we have 348 / 45 = 7.73333 precepts / year.
2500 years * 7.73333 precepts / year = 19,333.333 precepts.
Hey, that's not too bad at all, in any case it's a lot less than 740,000 !
Who wants to think about what they may be and start typing them in for use at Treeleaf???
Gassho
Ken