What are people's view on allowing a melee rogue to make sneak attacks at more than 30 feet range using Gloves of the Shortened Path?
i.e. Rogue stands 100 feet away from enemy and uses GotSP to flank enemy with a colleague...
Would you say he can sneak? or not? (saying his eyes to see vital spots are too far away)
Not possible.
You are in your own square 100' away. No flanking. Your hands are IN your opponent's square. No flanking. You cannot put your hands into a square adjacent to the enemy and then attack that enemy - you can only attack enemies in the square you've designated, not adjacent squares.
The 30' range has nothing to do with it.
Your vision has nothing to do with it, but you do need LOS to see the square you designate with these gloves.
OK, fair point, the attacking hands are in the enemy square (odd that it refers that you cannot flank with YOURSELF, whereas it should say you cannot flank with anyone)
Slightly different scenario then, rogue is greater invisible, enemy is denied dex bonus to AC, but the rogue is still 100 feet away.
Can she sneak now?
Yes. Your hands enter their square and attack them with the benefits of invisibility. No different than if you stood next to them doing the same thing.
The 30' limitation you're worried about only applies to ranged attacks. This is a melee attack so it is not applicable.