KL is checking its options when it comes to fleet renewal. These options are 777, 330/340 or 747X. When they were negotiating the merger with AZ, they were discussing standardized fleet issues, especially long range. Although KL is likely to stay at Boeing (they even share an engineering facility at Schiphol), they could still choose 330/340 and thus reach more fleet communuality with NW. Combined orders are propably not possible now, since KL doesn't want to spend money on fleet renewal now.
On the other hand, with all the possible new Wings partners (Malaysian, Continental, Alitalia, Air China, Thai Airways, Kenya Airways??), you can divide the alliance in a Airbus and Boeing camp and offer facilities for both. Commercially also interesting since this is a possibiltiy to offer your engineering skills to any airline in the world, like Lufthansa is doing very profitably.