One of the main wheel manufacturers here in the UK is TSW, they do a 4X98 fitting. They must export as well. They have a very wide range of wheels to choose from. My only reservation is that they are so common, in the UK at least.
Thomas, as you know i have O.Z superleggeras on my 155, they are one of the best purchases i've made, and as i've said elsewhere they are very light especially compared to my original 'telephone dial' alloys. if you can get hold of them you won't regret it trust me!
Going by what my wheel suppliers told me a company called 'Motorsport wheels'(01375 489500) are the only importer in the UK for O.Z's, don't know about elsewhere.
Hope this helps,