what width are you going for? 3-4" of dish is quite a wide rim, that would be an 8j.
rims of that size are still reasonable to perchance from Japan off yahoo auctions.

as someone whos been thru the rim widening game before it goes something along these lines.

purchase narrow rims... say 300 set.
purchase new rim outers - 150 a rim.
get your rims split (SSR mesh are all welded down the centre) - 10 each
get the spigot of the barrel machined to suit the SSR centre - 10 each

then if you get them welded back together, need to be polished etc... extra money there

min spend is around 1k. unless you are or have a mate who is a machinist.

These are volk mesh 13x7&8j - these could cost you as little as 800 into aus.