This is one that I happened to have in a file I sent to a friend. Mine at home (I am at work now) is just as you say, one to go up in the list and one to go down and then one to execute it. Here is a single modified line for it. Fill in the blanks.....
set model-1 "set select-model-back vstr name-20;echo [ (put name 1 here) ];set execute-model vstr name-1;set select-model vstr model-2"
bind (key) "vstr select-model"
bind (key) "vstr select-model-back"
bind (key) "vstr execute-model"
Thats the basics of it. And believe me I need it with 20 names and models, prob be 25 by the end of the week!
Just play the game......do not complain about it!