MIKESILV

Couple of quick things:
a) MIA/LHR is about 4400 miles opposed to about 3950 for ORD/LHR
b) The MIA/LHR flight gets in at 0635 am the earliest pretty much of all your choices.
c) LAX/LHR is a tough upgrade much easier through the other gateways.
d) Any special reason why you are flying J on a separate BA tix?
The last time I flew BUD/MIA it was a AA codeshare on BA and the cost was not too much more than just MIA/LHR R/T
The return through LHR got in to LHR at 200 pm and with no later flights onward to MIA that evening, I got to spend the evening in London.... not bad thing in my books.
Besides its only about a 2 hour flight, you can live in coach for that cant you?.

I would shoot for MIA or DFW but get on the ball June is a tough month to upgrade if you wait too long.

Check out Expert flyer, right now I can see C2 out of MIA on 6/12 through 6/20

mike