3,000,000 Gp?!

[ffone]

If not using Pierce Magical Concealment, there's a 'Force' ranged weapon enhancement (+2 BPB, ignore ethereal-vs-material miss b/c it's a force effect, with other nice properties like ignoring all DR!). It works well with a Ring of Blinking both to ignore the miss chance, and because blink lets you ranged sneak attack most foes. 'Force' is also a nice way to bypass DR /epic without the ridiculous 10x cost increase of epic weapons.

Once you have that (and-or the aforementioned Superior Invisibility approach), and a Use Magic Device mod of 19 or better, pick up many wands of Sniper's Shot (L1 swift spell, no range limits on sneak attack for that round.) Now you can sneak attack at more than 30'. Aside from the obvious benefits of more range, many anti-invisibility abilities have range limits, including True Seeing, most Blindsight, and the ability of ethereal creatures to see into the material plane. The See Invis spell has no range limit.

Pick up several copies of the boots of speed (10 rounds of haste for 12K, free action to active one-round increments) to be hasted all the time. Also use a new belt of battle for each fight, with the caveat that sniper's shot competes with it for your swift actions.