Just last night on Flyertalk, word began spreading that there is now a targeted 100,000 points promotion for the same card for only $500 spend within three months. Since this is targeted, you can only apply if you have a specific invitation number and offer code (people have already tried calling in to apply with no success). However, many who already applied and was approved for the 50,000 points offer sent in a secure message via the Chase online messaging center asking politely to be matched to the new promotion, and low and behold, within hours most received a positive reply and an additional 50,000 points instantly posted onto their Ultimate Rewards account! Remember, this is in addition to the 50,000 points they will or have already received after spending $3000 within three months - for a total of 100,000 points.
Granted, this is a highly YMMV (your miles may vary) case, and everyone should tread carefully. Nobody knows if this points grab free-for-all will last another week or even another day. Unfortunately, I only applied for the Sapphire Preferred card last week since I was still finishing up my spend for the Citibank AA card. I was not instantly approved, so I'm still sitting around waiting. However, if/when I am approved and the card shows up on my online account, I will immediately send in a secure message asking to be matched to the 100,000 offer. Either way, this is a great promotion and I will be happy whether it's 50,000 or 100,000. If you haven't already done so, I would recommend applying now!
(EDIT: This trick has officially been shut down. All agents are now denying the extra 50,000 bonus points and requiring the specific invitation code in order to take advantage of the 100,000 points offer. For those that received the extra 50,000 I doubt Chase will revoke the points so enjoy them soon. And unfortunately for the rest of us, looks like the the normal offer will have to do.)