An interesting idea just came to us. As Valve just had basically a huge giveaway to the TF2 community. When they made Ellis' Cap craftable, the ensuing trading frenzy and price inflation gave back quite a bit to everyone who had one of these formerly useless hats in their backpack.
As of today, TF2Stats.net has approximately 74,019 backpacks with Ellis' Cap. That is not a perfect # of course. There are likely more Ellis' Caps out there due to hoarding and Valve only gives Tf2stats.net a portion of the total outstanding backpacks. But it's the best # we have so let's go with it.
Prior to the update, Ellis was worth a scrap or two maximum. At today's current price of refined metal, around $0.55 each. 2 scrap are valued at 0.22 refined. Once they were changed to craftable they jumped to between a refined and 1.33 refined in value. Let's say 1.22 refined to keep it simple. That's 1 refined in value for 74,000 (at least) Ellis' Caps. Thus, Valve gave back over $40,000 to the community. Thanks Gabe!
edit: thanks Wolverine and BaconCat for catching our math error!