My ruling would be:
I allow a jump to be "paused" mid-air, considering it to be an artifact of the necessarily limited round-by-round nature. You'll be required to start your next turn with a move action to complete the jump, and if anything comes in your way meanwhile, you'll fall. I'd allow a bull rush against anything that comes in your way , to avoid the image of a dove halting a warforged, but in most cases a bullrush is still a bad deal if you risk falling into a chasm on a failure, and a bull rush costs a standard action instead of a move action, so this is hardly good for the jumper.
You cannot make a coordinated attack as part of a jump without spring attack (since you cannot move-attack-move, normally), unless you're willing to fall after attacking (the idea being that if you consider the attack to be part of a charge which involves a jump, then sure, you may, but then you're done after the charge - and would fall). You fall no matter what after the attack. I would allow the jump-attack in principle, since it's just too cool for a PC, but the character would take the prone + charge penalties from having charges and fallen prone, and standing up is a move action which provoked AoO's.