Google is one of the worst ways to look for anything, because of all the 
extra crap you have to wade through.

I don't know if this is what you want, but the site indicates two things of 
interest.
1.  The Channel Master 1650 is out of production.
2.  They have it in stock.
If you are just anchoring a wire to the top, guying might be nice but maybe 
not necessary, since wind loading is minimal.
The way as I understand it, the Alpha delta antennas use the support as the 
ground side of the antenna.  fiber glass is therefore not a good idea, 
unless you run a wire down from the antenna to the aluminum mast.
Now 50 feet minus a bit for sections.  $177, plus shipping.  Tell us what 
they have, and if this link becomes an antenna support.

http://www.3starinc.com/channel_master_cm-1650_telescopic_push-up_50_foot_16_awg_galvanized_steel_antenna_mast.html
H T Kaufman MSW LCSW
Adaptive Technology Instructor