Well, *Net blocking strikes again. All of the LX availability I saw on ExpertFlyer was non-existent as far as UA was concerned. I have been able to piece something together. It is longer that I was originally wanting, but what's the difference between 3 weeks and 3 weeks plus a few days I still have a couple of small changes to make (rez is still on hold). Current itin is:

SNA-SFO (UA Y)
SFO-IAD (UA C on a 777)
IAD-LHR (UA C on a 763 but not on the flight listed on the UA site....)
LHR-ZRH (LX C)

FCO-FRA (LH C)
FRA-ORD (UA C on a 744)
ORD-DEN (UA F on a 752)
DEN-ONT (UA F on a 320)

The changes I still have planned are:
Waitlist for F on the first segment (SNA-SFO)
Drop the LHR-ZRH segment. We are now thinking of going form LHR to Paris via train and then stay in Paris for a few days.
Change the ORD to DEN segment to the 777 a little later in the day since there is XC available and C on a 777 is better than F on a 752.

Amazingly difficult since my requirements were that constraining:
About 3 weeks in Europe
Get me to/from any gateway in Europe
Stay away from LH and UA 777's on the outbound to get a lie flat seat
Sometime in April, May, first half of June, late July, first half of August