Using MPlus for upgrade - most cost effective
 

Here is a conundrum. I am trying to travel business class from Dulles to Vienna (for two) by purchasing economy tickets and upgrading with miles. Dates sometime in April/May but flexible. I have 100K MP miles (and 160K Amex points, but that does not seem to help here).

I spoke to UA today and the best they can do is a B class flight (for 3065 and 80K miles) with a change at Heathrow and coach to Vienna, and same (coach VIE to LHR, business LHR to IAD). The K/T class is only 2600 RT, but then I have a $550 per person/per segment upgrade charge along with the 20K miles.

One alternative is the non-stop OS (Austrian) IAD-VIE, but this in B class is about $900 more (3900 + 100K miles) (including some enormous "government and fuel surcharge" fees - over $1000 for two).

A non-stop to VIE seems a lot nicer than a transfer at LHR in the middle of the night (body-time).

Any thoughts on alternate approaches to getting lower priced fare from another StarAlliance member?