I would like to see:
Standard action(attack, combat maneuver, normal spellcasting, triggering magic items, using full defense, etc.)
Move action(move, shift 10ft, drink a potion, some spell/power usage, stand from prone, draw an item from your pockets, sheat a weapon, etc)
Minor action(shift 5ft, draw a weapon, some spell/power usage,)
Interrupt action(attack of opportunity, specialized triggered interrupts).
1-round action(comes into effect on the start of your next turn and you are considered to be doing action outside your initiative window and there for can be interrupted): special and powerfull spellcasting, special aimed snipershots or similar.
Now, for the full-attack and multicasting options:
As we are probably will have 10 levels of spells and 20 levels total(before epics) and no base attack bonus per level, and very flat attack bonus overall, I would suggest the following;
* at level 7 you can attack as MOVE ACTION with -3 penalty to attack roll.
* at level 15 you can attack as MINOR ACTION with -6 penalty to attack roll.
for spellcasters:
* at level 7 you can cast a spell 4 levels lower than your max level spell as a MOVE ACTION(at level 7 that would be the "cantrip" as level 4 spells are you highest).
* at level 15 you can cast a spell 8 levels lower than your max level spell as a MINOR ACTION(at level 15 that would be the "cantrip" as level 8 spells are you highest).
of course if you try this with spells that are faster than standard action their casting time is also reduced by 1 category. at lvl 7 0-lvl cantrip that is cast as move action normally can be cast as minor action, and minor action can be cast as free action(limit 1 free action spell per round).