Does anybody know of a third party website (similar to Expedia or Zuji etc) where one can restrict a fare search to a combination of Oneworld carriers and actually book the ticket on the same site? This is in contrast to the ITA site where only flight searches are possible, or the Oneworld site where single sector or RTW itineraries only are possible.

I am particularly interested in pricing BUD-KBP and KBP-VIE on the same ticket, but individual Oneworld airline sites only allow this where codeshares exist. So I figure an independent site may offer this ticketing option. Is this called an open-jaw when the origin and final destination are different?

Try http://www.cheapoair.com/default.aspx?tabid=1683
or http://go.americanexpress-travel.com...=null&emg=null

Jetabroad is one the few Australian based online providers that offer flights that depart from anywhere in the world, most restrict to Aust. point of orgin.

For return and one-way searches, you can search by alliance, OW, SA, ST. Allliance search not available for mulit-city search.
For BUD-KBP / KBP-VIE, you can use the one-way search as BUD-VIE, with KBP as a stopover.

http://www.jetabroad.com/

Thanks folks - much appreciated - exactly what I was looking for. Although I do note that searches return some sectors that are flown by local partner airlines, but don't actually earn credits to Oneworld status....

Has anybody dealt with them/bought a ticket through them?

I need a PE ticket on QF, LHR-MEL-LHR, with a stop in SIN on the outbound. It appears you can't do that on the QF website because, in order to get the stop over in, you have to use the multi-city function - and as soon as you do that, PE is not an option. Had hours to kill today at BNE before a flight so figured I'd go to the ticket sales desk and get it done. Wrong ... "we only deal with same-day tickets and only domestic" - why QF has 3 people sitting in an airport ticket sales office to sell (only) same-day domestic tickets is beyond me. Thus, the alternatives become call QF (and wait for ever for them to answer, given my no-QF status) or go the MEL city QF travel center (or maybe call AA).

The jetaboard site is easy - tick the box if you want a stopover, say where and when you want to depart the stopover and here's your price - which in this case is a pretty good price - in fact, suspiciously good, compared with what the QF website wanted without the stopover (although the stopover should be permitted by the fare rules without additional cost).

Does anybody have any experience of buying tickets from jetabroad?

Well .... I pulled the trigger. It provided an Amadeus record locater that immediately showed up on CheckMyTrip and on the QF website. Did seat assignments on the QF website. So far so good.....

[Edited to add] Next day, received a confirmation email, including QF ticket number.

I have used Jetabroad in the past without problems. They notified me of a flight change plenty of time in advance. Just a single data point but they seemed professional. Only risk might be their fees for making itinerary changes.