http://www.litkoaero.com/
I use them. They've been slow as of late, shipping items beyond their supposed 2 week
limit. I love the skirmish trays, and I even go so far as to magnetize the bases and insert
metal squares into the tray so that my Wardancers can pretty much hang upside
down.
You can see pictures of painted versions of the trays here:
http://www.dakkadakka.com/wiki/en/The_Highborn_in_Question
Some issues with their trays:
Assembly is required (though not for the skirmish ones, obviously)
Sometimes, they're an extremely close fit to the point where paint and varnish
(or maybe oddly made bases) make lining up ranked models impossible.
When using them in a game, skirmish trays take away some of the flexibility of
a skirmish unit as you're rather limited in the unit's positioning.
Skirmish trays make close combat annoying. You have to take the models out to
line them up and put them back, unless your opponent is knowledgeable about
lining up and you can agree at the beginning how many models will be in contact.