Krytox from Dupont is reckoned in the Space/Automotive industry as one of the best Teflon greases available, but it comes at a stiff price, 29 $ for 1 oz. Dupont has some very informative data sheets, that indicates properties similar to both Call's and Shimanos drag grease.
Superlube is selling some cheap Teflon consumer products, data sheets is available and shows a dripping point similar to Calls
grease.
http://www.super-lube.com/high-tempep-grease-ezp-269.html
http://www.aaaindustrialsupply.com/superlubesyntheticgreasewithptfeteflon21030-.aspx
Have anyone tried Superlube Teflon greases for drags?
Read that Teflon will melt at 300 degrees Celsius, but will keep it's lubricating abilities until 600 degrees Celsius, a fact that seems to apply
to all Teflon products.
NB. Another interesting Teflon grease is Mobil SHC 462, with a dripping point of 464 F
http://www.mobil.com/USA-English/Lubes/PDS/GLXXENINDMOMobil_SHC_PF_462.aspx
the only thing i know is that cal's melts at 500 deg F and shimano grease melts at 300 deg F. both are $7 per ounce.