I (storm wizard) was able to get the heal for a million badge. It did require the help of three friends to assemble the correct number of heal boosts to achieve. It may be impossible to get it solo. Need plenty of guiding light and brilliant light treasure cards and the regular spells from a life wizard. If I remember correctly we used a total of 9 or 10 of these and used a flowering dryad treasure card. Gear that boosts outgoing for the caster and plenty of incoming for the wizard that receives the heal is a must (clothing and equipment). A pet that has the outgoing and incoming helps too. Good Luck.
Let's see how high my heal can get. :D I'll be back later with the results.
Edit:Success! 26056! I had a ton of fun with this experiment! Even though I had less blades/pips/cards then I wanted, I still got a good healing. And, guess what? I didn't critical. (I should have. :P) I didn't have the Eye of the Bartleby TC, full pips (I had 3 regular, 4 power) or critical so, the heal was a bit less then what it should have been if everything was perfect. As for the healing incoming/out coming, I had 50/12. I did this solo, btw. :D
I've gotten the one million heal. It took a bunch of tc, amulet healing blades, sanctuary, auras, shadow seraph, and a nice critical to finish it off. Its not impossible but i would imagine that only life wizards can do it without much trouble. As for the other schools... Good Luck :)