I would suggest a Warforged Artificer who uses the replacement levels and grabs the Craft Construct feat. Arfiticers normally only get Craft Homonculus which is good, but won't allow the creation of non-homonculus construcst that you might be interested in.

If you were a human I would suggest the Heir of Siberys prc.

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There are other feats from the Eberron books which allow improved constructs or homonculi that might interest you.