I use Hammergel in their little flask, in a holder designed for it that velcros to the toptube. A stem box would work also and be a bit more flexible-you can put energy bars and gu packets in there.

Frankly, every time I see a jersey at the LBS without 3 good sized pockets I go, 'gee how nice' and put it back on the rack. There are plenty of jerseys out there with pockets so I see no reason to suffer without. On long rides, I always carry a banana back there and stuff a few Luna Moons or an energy bar in as well. I can't imagine not having them on a long ride.