Not sure how easy this would be to do. I would ideally like this from a UK based person.

20mm solid aluminium.

Either

four 330mm sections each with 3/8 female thread one end and male thread the other. Top 200mm of two of the sections to have approx 200mm of grooves

or

one 950mm section and one 330 section. Same thread details as above. 200mm of each section to be grooved.

Thread size not restricted to 3/8's if impractical, but would need a convertor to go to 1/4 20tpi. I know I can pick up a 3/8 to 1/4 convertor easily.
May also need a right angle handle, but will disscuss further based on how any quotes come in.

Thanks
Richard