i'd say davis would be the place to go for strings. but do they have sunbeams in stock?
i used elixirs a long time ago. also tried DR extra-life black beauties.
from these experiences, i hate coated strings.
the first problem is cosmetics- the elixirs would flake rather easily, while the black beauties would be discoloured, which looks hideous. you could change them but that totally defeats the purpose of using long-lasting strings.
secondly i just didn't like the tone. coated strings would deaden very gradually and slowly, and within 2 months or so it would be nowhere near their initial 'freshness'. this is in contrast to non-coated strings, where it takes a day or two for the strings to break in, after which the regression would be somewhat similar to coated strings anyway.
coated strings generally feel better to the touch. but some strings i've tried are pretty easy on the fingers. my sadowsky blues are pretty good to the touch even though i use stainless steel sets instead of nickel.
i've also used products such as stringlife, which are pretty effective, although they have their limits. it does, to a certain extent, prolong the life of the string and makes it feel better, which is also the promise of coated strings.
so basically, personally, i would never again play through the entire lifespan of coated strings. they don't do it for me.