For touch spells, (shocking grasp/vampiric touch/joy buzzer, etc) I'd thought it was clear that touching the target completed the spell. If you're holding the charge, for whatever reason, then the spell can potentially be disrupted by someone thwacking you with a dead cat or whatnot (Concentration Check v. DC of dead cat).
If they're moving, though, it would depend on the casting time of the spell. 1-action = move and zap or zap-and-move. 1-round = spend the first round preparing the attack, second round move-and-release or release-and-move. "Move" can, of course, be replaced with "move-equivalent action".
Example: Ferro the wizard has his shield on and a sword in his hand. He uses a MEA to loose his shield (doesn't feel like being unarmed, just unarmored. Ferro's dumb.) and then casts Shocking Grasp. He can now touch anyone he can reach and zark with the spell. However, his target's 10' away. So Ferro holds the spell. Next round, he steps up (Move) and connects with the Shocking Grasp (zap). As I rule it, he does NOT have an NEA left over to re-ready his shield.
Sound correct?
~M.