If you want your hot water to reach your shower more quickly, remove the flow restrictor from the shower head. Seriously. I did this in the hopes of just getting a more satisfying-feeling shower and an unexpected side effect was that the hot water reached the shower in about 1/4 - 1/5 the time it used to take.
Some of you may be worried about what such a move would cost. I live alone and only pay about $7 - $8 a month for water, so I really wasn't worried about the effect on my water bill. I did look for an effect, though, and if it was there, it was only a matter of a few cents.
For those of you who shout, "OMG teh envir0nm3nt!!1!" - I have a septic system, so all that gray water is just going back into the ground anyway. And besides, if the People's Republic of Canada doesn't feel the need to regulate people's water flow rates, why should we here in the good ol' US of A?
Flow restrictors are usually separate, easily-removable components of shower heads and faucets. Do yourself a favor and take them out. You'll be amazed at how much better a shower feels when the volume of water hitting your skin increases dramatically.