Here's what I have copied down. As you can see, I made a couple attempts at it but I think some of calculations I made were incorrect.
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Distance Archer
Base race: Half Minotaur Goliath (remember, for every size catagory larger than medium your range goes up by 25%... so this guy gets a +50% to range) with Far Shot and Cragtop Archer 5. He weilds a Greatbow (base 130ft range) +1 of Distance, so his base range increment is 260ft. Cragtop Archer 5 lets you shoot at max range with no penalty (as a full round action) so that's 3900ft with no penalty. One level of Binder with Improved Binding lets you bind Malphas, whose bird lets you see at that range with no problem. Anyone trying to spot you has a -390 to their spot check, so running really doesn't matter much.
Now make the bow out of that wood that turns your arrows into Brilliant Energy automatically, and you can shoot from outside a dungeon into it and kill people entirely remotely.
You take a level of Binder so you can bind Malphas, which gives you a bird that can scout ahead for you. You see and hear everything the bird sees and hears, so your bird plays spotter. As a result, you stay safely hidden so far away that they can't possibly find you, while your bird makes sure you can always see the enemy, even through cover or through rocks (or through a mountain, if you like!). You can thus keep your bird with your party in a dungeon while you set up camp outside and pelt anything nasty that your bird detects with arrows.
So to reiterate: you have a character that's doing at least 3d8+10 damage per hit (which isn't bad for an archer), who can fire from complete safety, even through walls and rocks and dirt. His range is incredibly good, better than anything a smaller race could likely pull off. He's able to spot targets remotely and act like long range artillary. All in all, he's exactly what the OP wanted. Admittedly, he can't shoot through dirt until he gets brilliant energy, but still.
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At least 3 levels in Cragtop Archer (for an ability that gives an extra 5 increments for a total of 15, rather than 10 - RoS pg101)
Far Shot (+50% per increment)
A Composite Great Bow (130ft increments) with the Distance magical property (double increment value for 260ft). (CWar)
Range Weapon Mastery - Piercing (adds 20 feet per increment - PH2 pg 82)
Maximum range - 6150 feet (1.16477 miles, 1874.52002 meters, 1.78452 km)
great bow 130 (CW)
dragon bone +20 (draconomicon)
far shot *1.5
distance *2
crag top archer arcing shot (15 range increments)
(150+150+75)*15=5625 feet
345 feet beyond 1 mile
this can be acheived at 10th level.
if it is possible to combine this with deepwood sniper,
then 150+150+75+100=475*15=7125 approx 1.35 miles
"Arrows, flight" from Arms and Equipment guide increase a bow's range increments by 25ft. Dont forget those!
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composite greatbow: 130'
made of dragonbone : +20'
+25% from powerful build (assuming goliath or some such race): +37.5'
+100% from being colossal (item of giant size): +150'
x2 from the distance weapon property: +337.5'
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675' for the bow itself Actually, the distance property is not part of the base, making the base a 337.5 feet, and everything else would have to be based off of that, cutting you're total in half +337.5, more or less. Read about D&D stacking and addition/multiplying.
x2 from item of accuracy: +675'
x2 from item of wind tunnel: +675'
+50% from item of hawkeye: +337.5'
x1.5 from far shot feat: +337.5'
10th level deepwood sniper: +100'
flight arrow: +25'
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2825' range increment
So a 3rd level cragtop archer would be able to shoot an arrow 42375', or 8.03 miles.
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My Ranged Distance Try (Hopefully to get farther than 8 miles
Goliath (Races of stone
Psion 17
Cragtop Archer 3
250 PP
69 PP used (17 times)
Calculations go as follow: (1st try, looks incorrect as Extend Range doesn't * after, but the base)
great bow 130 (CW)
dragon bone +20 (draconomicon)
far shot *1.5
distance *2
crag top archer arcing shot (15 range increments)
(150+150+75=375)*15*17(Extend Range Augmented)=95,625 feet or 18.11 miles
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2nd Try:
The Bow:
composite greatbow: 130'
made of dragonbone : +20'
+25% from powerful build (assuming goliath or some such race): +37.5'
+100% from being colossal (item of giant size): +150'
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Totals: 337.5 x 17(extend range) = 5737.5
far shot(PHB Feat) *1.5 (+8606.25)
distance(DMG) *2 (+11475)
accuracy(CA) *2 (+11475)
wind tunnel(Magic of Faerun) *2 (+11475)
hawkeye +50%(CD) (+2868.75)
flight arrow(A&E) +25'
crag top archer arcing shot[RoS] (15 range increments)
(5737.5+8606.25+11475+11475+11475+2868.75+25=51661.75)*15 = 774,926.25 (146.76 miles)
1 mile is 5280 feet.
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3rd Try (without raising a manifester level - Most legal way of doing it)
The Bow:
composite greatbow: 130'
made of dragonbone : +20'
+25% from powerful build (assuming goliath or some such race): +37.5'
+100% from being colossal (item of giant size): +150'
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Totals: 337.5 x 5(extend range) = 1687.5
far shot(PHB Feat) *1.5 (+2531.25)
distance(DMG) *2 (+3375)
accuracy(CA) *2 (+3375)
wind tunnel(Magic of Faerun) *2 (+3375)
hawkeye +50%(CD) (+843.75)
flight arrow(A&E) +25'
crag top archer arcing shot[RoS] (15 range increments)
(1687.5+2531.25+3375+3375+3375+843.75+25=15,212.5)*15 = 228,187.5 (43.21 miles)