The closest I have to that is a full flex,7 1/2 foot 3 wt "Tippet."  I've had it for 15 years, and still use it once or twice a season in the smallest of small creeks.  However, it is a true noodle stick.  Just like bamboo, only lighter and not as cool.[

]   Because of that, I seldom recommend it to anyone, and its no longer made either.
 
I've cast the Sage ZXL on a couple of lawns and in a pool inside an auditorium, but you're right, its not a LL.
 
I have long been one to dismiss and dislike most of the newer, faster graphite fly rods in the last 10 years.  However:
 
I'm going to have to try a light weight Helios in a 4 wt. this year.  The mid-flex is around 2 ounces as I recall.  I'm pretty sure the Sage LL's are a litte more than that.
 
I can't believe how light that 8-wt is.  I used to HATE chucking an 8-wt in salt water, or even in fresh for pike and salmon.  It was just too much work most of the time.  After casting the Helios this winter though, I can do some more of that!  My "older" 8 weights and the titanic 11 wt. are both on Ebay as we speak.  They're tanks compared to the Helios.
 
And to the original poster, just get what you like and/or can afford in a 3 wt, and you'll probably like it.  Light fly rods are more simplistic than the bigger ones because casts are usually much shorter in actual fishing situations.  I always recommend trying before you buy.  Most fly shops will let you make some casts first.
 
I wouldn't sell my LL's for $1,000 a peice today though.  They just happen to be a perfect fit for me, and that's priceless.
 
Now, if I could get off the dang lake, and get caught up on all my postponed winter/spring chores, I could actually go fishing instead of rant about it!  Rumor has it the dreaded little olives are popping!
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