Well that is a bit of a challenge....
Alright Mirliton has a smithy with an anvil but you would have to buy the whole thing just for the anvil....
http://www.mirliton.it/product_info.php?pName=smith-workshop&cName=historical-2528mm-diorama-kitsMega minis, on the other hand, makes a blacksmiths shop with pieces that can be bought individually. The link is to their catalog, (they have a store on ebay) page 7 has the blacksmith tools. My first concern is it might be a bit small but then the Hasslefree minis are slightly smaller as well so it might work.
http://www.megaminis.com/MEGA/CATALOGS/MegaMinis-DUNGEONDECORcatalog.pdfFoundry miniatures has a blacksmith set in the civil war collection with an anvil as well:
http://wargamesfoundry.com/historical_ranges/single_packs/english_civil_war/british/blacksmith_ecw005/There are a fair number of standard miniature anvils ranging from toys to tools for jewelry making; one example of a model anvil:
http://www.reindeerpass.com/anvilhammerandtongs.aspxNow these are all rather plain and might not look as nice as GW's so a dramatic dwarven base might be necessary to give the unit a more imposing profile, for example:
http://www.sciborminiatures.com/en_,shop.php?art=732or...
http://www.sciborminiatures.com/en_,shop.php?art=865There are also a few dwarf minis with anvils built in, if you were thinking of going that route...
http://juza-miniaturas.blogspot.com/Of course the best route might be conversion or to scratch build one....
regards,
IT