yea, i also work at a scion dealership, very close to scion HQ, and i can tell you now, that no order type of forced induction is being researched and developed for the tC. Everything you are hearing is just a rumor.
As for turbos lagging, that depends on the size of the turbo, and the size of the charge piping, there are turbo kits out for the tC right now that hit max boost before 3k RPMs, hell, the supercharger doesnt hit max boost till redline, but thats for obvious reasons.