Darren,

Are you really sure that AA LAX will issue you the ticket in the US and allow you to buy it in USD converting ex-BUD prices? If so, you're a lucky man and congratulations. The common rule is that no SOTO issue is permitted with OWEs (except ex-Canada). (There's some info about this at http://www.flyertalk.com/forum/Forum83/HTML/000316.html . Also, you might want to refer to Guy Betsy's comment at the bottom of the page at hsi.chang's website http://www.geocities.com/osointer/ownotes.htm )

As for the issue regarding the number of stops permitted in the continent of origin, yes there are some exceptions for a few countries where three stopovers are permitted. If your agent allows you three, take it! However, I just wanted to let you know that the official rule, according to BA Hungary, is that ex-BUD OWEs only allow two stopovers, one an international gateway, and one anywhere else.

And finally, ending your journey as open jaw is a new idea to me. Personally, I'm not sure how it would work, since I have no idea how the fare is going to be calculated.

Good luck!