Soeren,
make sure that the frame material won´t scatter the light.
Why? Look at
www.versamask.de, Klaus Zoepfl designed a VERY nice easel system - the masks are held in position with the help of small pins - bare steel... now, some users have reported that these in the corners reflected enough light to spoil the frames!
On suppliers - I don´t know any danish... here are a few native Danes (modafoto, Aggie, others). But I guess you plan to "import" within the EU, from Germany?
Since bw is dead in my region (1992, when I -aged 14 or 15- started darkroom work at school) I depend on mail-order, too. I buy from three suppliers:
www.phototec.de - the shop of Peter Loeffler, a kind, helpful man. Good prices, subscribe to his newsletter for special offers! He sells most brands (but Maco), including the smaller Calbe, Amaloco, Spur and gave "us" a good forum for exchange (the Versamask started at that forum!).
www.fotoimpex.de - I buy my Foma Variant, Fomatone MG paper and Foma/Efke films there. They are the partners of J&C, Mirko is good, either, but hard to get by at the moment. In recent years he sponsored the beginners BW and E6 workshops at the de.rec.fotografie-Gettogether with chemistry and papers.
The third is
www.phobatec-shop.de, a retailer on batteries and film. Mr Ritt has the best prices available to a smaller customer like me. APX100 in 120 for 1,79EUR, HP5+ in 120 for 1,85, thats very hard to beat.. and his battery prices are very competetive, too.
Caveat: Add 16% Umsatzsteuer and ca. 2% parcel insurance to his prices.
If I want Ex-east bloc stuff and can afford to wait, I buy in berlin. If I depend on the stuff, I order from Herrn Loeffler - there is almost always an item out of stock with Fotokemika/Foma/Forte. :-( If I want to be pennywise, I buy "Kurzlaeufer" (outdated film) and make a larger order with a few friends at Phobatec.
Forget Brenner - he carries everything, but at none-competetive prices.
Hilft das?