is it just me or it is really nearly imposible to find ?

[Nacho-RT74]

a 68/69 RR-GTX cluster with 150 speedo ?

 

[5wndwcpe]

They pop up from time to time. Usually run $150-$350 depending on condition.

 

[ply64post]

a 68/69 RR-GTX cluster with 150 speedo ?

Nacho

Check this site.
They are listed under B-Body used parts.

http://www.tonysparts.com/BrowseResults.asp

$275 68-9 150 MPH LONG STYLE SPEEDO CLUSTER HAS #s 1-15 ($425 W/RECHROMED BEZEL + RECOLORED NEEDLES)
$375 68-9 150 SPEEDO CLUSTER, HAS #s 10-150

Hope this will help.