it was close to happening before oil shot up. now that it's coming down again, hmmmmmmm
There are only three places I've really heard any OO/WN talk in any kind of detail: OO jumpseats, WN jumpseats, and FlightInfo. So, you can take any and all of this however you wish.
That said, I think there COULD be something to this. What little I've heard from other sources beyond other pilots/DXers involves the E-175/-190 and the CRJ-1000 (two aircraft types that are bound to make pilots on both sides cringe).
I can see customer/PR reasons for wanting the E-Jets...they look similar to the 737, therefore less likely to put-off fickle pax who are used to seeing WN paint on aircraft with engines under the wings. For us, it sounds stupid...but for John Q. Pax, that perception is a big thing.
The synergies (I do hate that word) are there for a successful codeshare...the most successful/financially stable major pairing up with the most successful/financially stable regional...
I dunno, man...as long as there is a United hub in DEN, I'm not sure they would allow it. However, now that the exclusivity deal UAL had in place with SKW at LAX is over and done with, I could see some LAX to lower density markets, as well as LAS/DAL/BWI feed. MDW could work if the aircraft were CRJ's (at least, initially) because, technically, you already have a ton of crews in Chicago...they would just have to hitch a ride on the Orange line instead of the Blue to get to work.
Who knows...this business throws better curveballs than Bert Blyleven ever did.