Sculpting Steel comes to mind, as (on a more limited basis) does Mizzium Transreliquat (which is less helpful for small mana artifacts but could work if you have artifacts that make more than 3 or can come up with a red mana to make a permanent copy).
EDIT: Gee, how did I know that I wasn't going to spell "Mizzium Transreliquat" right on the first try.
Honestly, if you want to ramp using a blue/artifact deck, you're probably better off not bothering with the copying effects and just going straight for the mana-producing artifacts. Everflowing Chalice is at least as efficient as Copy Artifact copying Seat of the Synod unless you really need colored mana, Silver Myr and the Signets give you colored mana, and there are bigger versions like the Thran Dynamo and Gilded Lotus.
Just curious as I'm going to try to make cards like this mana ramp for mono-blue using seat of synod and Darksteel Citadel.
Blue or Colorless
Thanks
EDIT: Gee, how did I know that I wasn't going to spell "Mizzium Transreliquat" right on the first try.
Prototype Portal?
(No offense, but that deck idea sounds awful.)
ゆっくりしていってね!!!
I’ll be locking it