Join Date: Jan 2005
Location: Toronto, NYC, somewhere on planet Earth
Programs: UA 1K, AA ExPlat, Hyatt Diamond, SPG Plat, Marriott Gold
Posts: 8,289
Given that only the US-based airlines offer UDU (and pretty well only GS and 1K and Plat will get them), I think it is a stretch to get other * members to offer it to UA flyers when they do not offer it to their own elites.
As ORDnHKG noted, other than F lounges what else do you want? * Golds, incl 4 levels of UA Elites, get complimentary access to lounges outside the US. In addition, the international lounges of other * carriers are much much better than UAs United clubs!
United has an agreement with LH to apply SWUs at the airport, subject to availability. AFAIK, no one can apply their upgrade mechanisms (other than the * alliance upgrades on premium and full fares) onto UA.
Seems you are asking a lot of * members, but offering very little in return!