Haven't heard of the other but these days Endless Summer is a series and not a specific cultivar - presumably you are talking about The Original ('Bailmer').

Which is of course a patented invention belonging to Bailey nursery.

Hydrangea plant named `Bailmer`

http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=10&f=G&l=50&co1=AND&d=PTXT&s1=bailmer&OS=bailmer&RS=bailmer

the one I read about has a long blooming season. It blooms on new and old stem...

They're all supposed to be long blooming, hence Endless Summer.

Endless Summer® Collection

http://www.baileynurseries.com/our-brands/endless-summer/

I see the L.A. Dreamin' ('Lindsey Ann') is a patented invention also. In this case belonging to an entity named A.T.J. Holdings.

Hydrangea plant named 'Lindsey Ann'

http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=5&f=G&l=50&co1=AND&d=PTXT&s1="lindsey+ann"&OS="lindsey+ann"&RS="lindsey+ann";

Are you still looking for one? I have one but it's just coming back to life I couldn't take cuttings right now. But if your interested I could take some later on?

oh , yes, I'm still looking, thank you

Meyabut.... I have several house plants as well as kwanso lilies, trumpet vine, woody lantana, century plant babies, a wide variety of seeds, coral honey suckle..... ummm house plants.. I have parlor palm, ivy, I could get you christmas cactus start

Would you trade for a parlor palm and a kwanso lily?