OK, so I finally applied for/received the SWA Visa. Upon activating this afternoon, I browsed WN's list of preferred partners and...
http://www.southwest.com/rapid_rewards/amex.html
Starting April 1, 2009, American Express Membership RewardsŪ points can now be immediately transferred into Southwest Airlines Rapid RewardsŪ credits.
Southwest Airlines participates in the Membership RewardsŪ Program from American Express. Points earned for purchases made with the American Express Card can be used towards various rewards including Award travel on Southwest Airlines.
1,500 Membership Reward points may be transferred for one Rapid Rewards credit (24,000 Membership Reward points = 1 Award).

When the heck was this announced???!!!! I mean, don't get me wrong - I'll enjoying using a free RR ticket just for having gotten the credit card. However, it seems to me that as PLAT, I'm going to have a lot easier time racking up MR points for transfer than I will using SWA Visa - for the simple reason that Amex maintains an online Bonus Points Mall, on which I earn a whopping four points on each dollar of spend, as opposed to WN's paltry 1:1.
Guess I should look at it this way...many vendors don't take Amex...can't hurt to rack up points towards my RR account that I'd have otherwise missed using my Marriott Visa...then I can augment later.
But is there something I'm overlooking here? Seriously, I can't believe I somehow missed this announcement...!