If you have Harper, then I think the more obvious choice is elf wiz 18 / ftr 2: INT-based PM / AA hybrid. Caster DCs & Spell Pen will suffer a bit, but you get the fun of Manyshot+IPS. You also gain med/hvy armor prof free for added PRR/MRR; max Arcane Fluidity to reduce ASF, ofc.
Stats: CON 12-ish, enough DEX to meet feat pre-reqs w/tome (best case:base DEX 15 + 6 tome), rest into INT
Leveling order: Ftr 1 is taken whenever you need the extra feat and/or +1 BAB. Ftr 2 is taken at lvl 20 so you have the BAB for IPS. For simplicity's sake, let's assume wiz 1, ftr 1, wiz 2-18, ftr 2. [You could take MS @ lvl 11 if you did wiz 1-10, ftr 1, wiz 11-18, ftr 2, but then you just delay something else until lvl 12.]
Feats (regular): PBS (1), Prec Shot (3), Precision (6), Insightful Reflexes (9), Manyshot (12), IC:Ranged (15), <whatever> (18), Overwhelming Crit (21), Combat Archery (24)
Feats (ftr): Rapid Shot (ftr 1 @ lvl 2), IPS (ftr 2 @ lvl 20)
Feats (wiz): the usual metamagics
Enhancements: 14 APs elf (AA unlock), 12 APs Harper (KtA, Strategic Combat), at least 21 APs PM (wraith form). After that, it's a question of whether you want Slaying Arrow (in which case everything else goes into AA); or you want more caster buffs (e.g., T5 PM, lich form, maybe Evo Archmage for MM spam).
It's still far from ideal, but I presume you knew that going in.