My only lament was that up until now there was only the 4 mods: Insta-Share, SoundBoost, Power Pack, and the Camera (aside from the style shells)
Well, it looks like Mophie is the first to release an official mod comes from Mophie. The Juice Pack Battery mod.
Unfortunately, it looks like this mod is only going to be available at Verizon. It will be bigger than the Incipio power pack by offering 3,000mAh, but you will pay for it at $80USD (vs. $90CDN).
But, what looks cool is that it has the battery indicator on the outside (love those).
Hopefully it comes north of the border and/or incites others to start to come out with more mods. I'm banking on this being a really 'future ready' device.
Source: Verizon via Droid-Life