"in a length of" is a correct and usable phrase in written English.
It is often used to indicate a measure of time or distance. For example, you could say, "We hiked in a length of five miles."
I tied some safety knots in a length of rope.
The adornments are the actors themselves – French, Palestinian, African – led by the radiant Tunji Lucas, wrapped in a length of sky-blue cloth.
Baker enclosed a wad of cotton waste in a length of black veiling, commonly worn by women in mourning, which could be tied around the mouth.
But Federal officials have said that the destructive power of the Reno bomb had been enhanced by an explosive powder packed in a length of pipe.
To Elena Kats-Chernin's vibrant and seductive string quartet score, the dancers initially appear enclosed in a length of gold sari, an embryonic wrap that births them like brothers.
When wavelength is measured in metres, 1/λ represents the number of waves of the wave train to be found in a length of one metre or, if measured in centimetres, the number in one centimetre.
In the 1959 championship final against Hunslet at Odsal Stadium in Bradford, England, van Vollenhoven scored his most famous individual try in a length-of-the-field run on which he weaved his way through the entire opposition.
In the 1961 Challenge Cup final win against Wigan at Wembley Stadium in London, he finished off one of rugby league's greatest tries in a length-of-the-field passing extravaganza with Ken Large as they exchanged the ball several times while running past the opposition.
Nearby, a crescent moon hangs in space on a length of fishing line.
The terminal vertebra is abbreviated in length, with a length of less than one third that of the penultimate vertebra.
Thread a needle with a length of thread in a colour that matches your garment.
