Is this the future of collecting?

[steve B]

And they did a bunch of stuff like that with the Etopps back in 2004. Special event cards for the playoffs and WS.

I thought it was a great idea.

Some countries also do this with stamps and sports, the UK and I think Australia have done print on demand stamps for Olympic gold medal wins.
Our rules in the US have changed within the last few years to allow someone living to be on a stamp. We haven't done it yet, but it's possible.

And you might be able to slide a Canseco image past either Stamps.com or Zazzle and make your own "stamps". They've been a bit touchy about copyrighted images or images of known people since a few journalists slid images through during the testing period -Unabomber, Hitler as a child etc. So they might catch it and refuse.
They're valid postage but the USPS considers them to be meter imprints not actually stamps.

Steve B