As far as ApR goes, Spell Rebalancing changes the Level 4 Cleric spell of Divine Power so that the "caster gains attacks per round as a fighter of equivalent level (does not stack with multiclass fighters' ApR)." True, this is a mod, but who doesn't use rulechanging mods like this these days? I think Druids are still out in the cold where ApR is concerned, but at least they can use Belm.
Yeah, but does it actually check out the characters proficiency in the weapon in hand, give them the exact ApR they deserve from being 13th level cleric(+1) that has the full extend of the proficiency in Grand mastery, so the one handed weapon jumps from 1 attack per round to 3.5 or 7(from 2) with Improved haste, does it? Because the rule changing mod(BG2 Tweaks) makes the grand mastery extra powerful(1.5 to 2.5 ApR)... see, items for example can grant the power of having Weapon Grand Mastery even to non warriors...
From the spell description, "The caster gains extra attacks as a fighter of the same level, thus an extra half an attack per round at 7th level and another half attack per round at 13th level."