I found a great place today
http://www.andyshardware.com/index.html
I walked in there by word of mouth from a parts store looking for some u-bolts and they have everthing!
Their bolt selection is amazing. They have everything from 1/4" to 1-1/4" in all lengths, grade 5, grade 8, and fine thread. They even have the same huge selection in stainless and metric. I'll never go to the Nut Store on Gessner again - they aren't even open past 5 or on Saturdays...
I always have a hard time finding things like a 9/16" x 4.5" long grade 8 fine thread bolt - but they had it - in stock!